Light source bodies for filament tubes and ARC tubes

ABSTRACT

Manufacturing equipment and manufacturing process steps that improve upon prior art processes for the manufacturing of filament tube and arc tube light sources, their components and subassemblies, and lamps employing said light sources. A double ended, tipless filament tube or arc tube light source incorporates a drawn-down tubular body, and one piece foliated leads with spurs for process handling and for spudding into a filament with stretched-out legs. Bulged ends on the body provide a novel cutoff means, facilitate a flush-fill finishing process, and enhance mounting and support of the light sources in lamps. The foliated leads are made from a continuous length of wire in a process including foil hammering and two-bath AC electrochemical etching. Cost-reduced light source and lamp production enables affordable household consumer lamps, even when containing two series-connected halogen filament tubes. Safety benefits ensue from series connection, especially in combination with disclosed body and filament constructions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/702,011titled: APPARATUS AND PROCESS FOR FINISHING LIGHT SOURCE FILAMENT TUBESAND ARC TUBES, Publication No. 2005-0092025.

This application also relates to the following U.S. patent applications:LIGHT SOURCE BODIES FOR FILAMENT TUBES AND ARC TUBES, Ser. No.10/701,808, now abandoned; ONE PIECE FOLIATED LEADS FOR SEALING IN LIGHTSOURCES, Ser. No. 10/702,155 issued as U.S. Pat. No. 7,107,676; SPURREDLIGHT SOURCE LEAD WIRE FOR HANDLING AND FOR ASSEMBLING WITH A FILAMENT,Ser. No. 10/701,832, now abandoned; MOUNTING LIGHT SOURCE FILAMENT TUBESAND ARC TUBES IN LAMPS, Ser. No. 10/701,950, now abandoned; and TWO-BATHELECTROLYSIS, Ser. No. 10/701,833, now abandoned.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to electric light sources and theirmanufacturing processes; and, more particularly, to said light sourcesin the form of a double ended, tipless filament tube or arc tube.

BACKGROUND OF THE INVENTION

Although a variety of compact light sources are available, those withimproved energy efficiency (lamp efficacy) are generally accompanied byproportionally higher manufacturing costs, and therefore by higherpurchase prices that often outweigh their perceived benefit to ordinaryconsumers. For example, U.S. Pat. No. 4,524,302 (Berlec; 1985) disclosesa general service incandescent lamp with improved efficiency having anouter envelope and an inner envelope. The inner envelope comprises whatis generally known as a halogen lamp: a filament tube of quartz or hightemperature glass, hermetically sealed around an incandescent filament,and filled with a relatively high pressure fill-gas including a halogengas. Among the objects of this invention are to provide a relativelyinexpensive general service incandescent lamp, to improve the arc-outresistance of the filament, and to operate at a low voltage so as toextend the life of the lamp while maintaining its wattage and evenincreasing its efficacy. The reduced voltages relative to a typical 120volt AC source may be developed, for example, by an electricaltransformer.

It is known that low voltage incandescent filaments are more rugged thanhigher voltage filaments having the same wattage, especially forcoiled-wire filaments, because for any given wattage, as the designvoltage is decreased the length of wire in the filament decreases, andthe diameter of the wire in the filament increases. Two patentsexemplify incandescent lamp designs that take advantage of this fact byproviding multiple filament tubes that are series-connected within anouter envelope. This reduces the voltage drop across each filament tubewithout requiring a transformer, however the cost of the inner lightsource is multiplied by the number of filament tubes provided. U.S. Pat.No. 4,498,124 (Mayer et al.; 1985) discloses a dual halogen bulbrectangular lamp assembly with the two halogen bulbs electricallyconnected in series for simultaneous bulb energization. The use of two12-volt halogen bulbs in a 24 volt reflector lamp significantly reducesthe possibility of bulb burn-out because the filaments required in12-volt halogen bulb units are made from shorter, thicker wire that canbe coiled much more loosely than the filaments required in 24-volthalogen bulb units. PCT publication WO98/14733 (Katougi et al.; 1998)discloses a light bulb with a plurality of baseless small bulbsseries-connected within a globe envelope, for improved earthquakeresistance. FIG. 8, for example, shows two double ended filament tubeswith wire loop outer leads hanging in parallel arrangement on oppositesides of a central support post.

Another factor that adds to the cost of lamps that incorporate filamenttubes (e.g., halogen lamps) is the desire to protect consumers frompossible non-passive failure of the filament tube. When an incandescentfilament fails at end of life, an electric arc may form between brokenends of the filament. Once started, an arc has very low electricalresistance and will draw as much current as the power supply allows. Inarc lamps, the power supply includes some form of ballast to limit thecurrent to a desired amount. Incandescent power supplies do notgenerally provide much ballasting effect, and rely instead on fusesand/or lamp construction to quench an end-of-life arc before it canproduce violent failures that may, for example, rupture thefilament-containing envelope(s)—i.e., to “explode”. For filament tubesthere is a small possibility of non-passive failure due to an arc thatoverheats the filament tube before the arc can be quenched by a fuse. Acommon solution is to make the outer lamp envelope out of a thick glassexpected to contain a potentially rupturing inner envelope. For example,U.S. Pat. No. 6,133,676 (Chen; 2000) discloses a double envelopedhalogen bulb wherein the outer glass envelope has a thickness rangingbetween 2 mm and 8 mm that is intended to protect a person or an animalcontiguous to the bulb from a bodily injury in the event that thetubular halogen bulb explodes. Chen's FIG. 6 shows an embodiment of hisouter envelope that is shaped somewhat like a common household lightbulb. Obviously, the heavy glass envelope is much more expensive than astandard bulb.

Another solution for containing rupturing filament tubes is taught byrelated arc lamp art. For lamps that incorporate arc tubes as the lightsource (e.g., high intensity discharge lamps), non-passive failure iseven more of a concern, particularly when the light sources are intendedfor household use and/or wherever they will not be contained inprotective “closed” lighting fixtures. U.S. Pat. No. 5,446,336 (Gleixneret al.; 1995) discloses an explosion-protected high-pressure dischargelamp comprising a protective body surrounding the discharge vessel andlocated within an outer bulb. The protective body comprises one or twotransparent concentric glass sleeves or tubes, at least one of which,preferably, is of quartz glass. The sleeves or tubes have open ends, andthey radially surround the discharge vessel, with the open ends beingcapped by ceramic centering and holding elements which are retained on alamp holder structure.

A solution for preventing rupturing filament tubes is disclosed by thepresent inventor in the November/December 2001 issue of IEEE IndustryApplications Magazine (incorporated by reference herein), wherein amockup of a 1972 experimental “Gemini lamp” is pictured and described ashaving “small twin tubes paralleling the central glass stem—theselow-pressure, 60-V halogen capsules would not explode . . . . [The] twosmall 60-V capsules [are] in series . . . ” (pg. 16). The picturedmockup has empty glass capsules, and the design of a filament for thecapsule is not disclosed. Likewise, the capsule's shape isindeterminate, and no lead wires or sealing foils are present.

FIGS. 2, 4, and 5 of the Berlec '302 patent illustrate some commonfeatures of filament tubes. FIG. 2 shows a typical quartz filament tube(22) with 1 mm thick walls that is double ended with an exhaust tube tipon the side of the tube. The tube ends are hermetically sealed by beingpinched closed over a thin molybdenum foils (28, 32) that aremicro-welded to inner (24c, 24 e) and outer (30, 34) molybdenum leadwires. The inner lead wire may alternatively be tungsten, and istypically welded to the filament, however FIG. 3 illustrates a techniqueof using the inner lead wire (24 c, 24 e) as a spud that is forced intothe single coiled end (24 b, 24 d) of the filament (24). It is knownthat this spudding process is difficult to automate given that a bluntwire end must be screwed into the coil in a way that expands the coildiameter. FIG. 4 illustrates a single ended filament tube (36) that isalso made out of a high temperature glass other than quartz. In thiscase, sealing can be accomplished on the round lead wires (38, 40)without needing foils. The illustrated filament tubes (22, 36) arerelatively bulky and heavy, and therefore require substantial mountingstructures (16, 18, 20, 42, 44, 46, 48) within the outer envelope (12).FIG. 5 illustrates a somewhat smaller filament tube that is onlysuitable for very low voltage filaments that are consequently shortenough to be mounted crosswise in the filament tube.

Several patents assigned to General Electric are indicative of theindustry's efforts toward cost-reducing the manufacturing process forboth filament tubes and arc tubes, particularly those small enough to beincluded in smaller lamps. U.S. Pat. No. 4,389,201 (Hansler andFridrich; 1983), incorporated by reference herein, discloses a method ofmanufacturing metal halide discharge lamps (arc tubes) on a horizontalglass blowing lathe which is indexed by a turntable through angularlyspaced work stations. A length of quartz tubing is formed into a lampbody having an enlarged bulbous midportion defining an arc chamber withtubular necks projecting in opposite directions. FIGS. 9 and 10 show thebulbous midportion (32) being formed by heating (132) whilelongitudinally gathering the quartz (120) and then blowing it out into amold (134). Exhausting, flushing, and filling are all accomplishedthrough the length of quartz tubing while it is captured in the lathe,thereby eliminating exhaust tube tips on the side of the arc tube. U.S.Pat. No. 4,810,932 (Ahlgren et al.; 1989), incorporated by referenceherein, and other related patents adapt and enhance the '201 patentedprocesses to disclose flush and pump flush processes yielding lightsources for both incandescent and metal vapor discharge lamps,particularly tipless double ended filament tubes that are suitable fordeposition of a reflective coating on their outer surfaces. FIGS. 1(a)-1(p) show the flush process implemented in a horizontal lathe. FIG.1( d) shows the filament assembly (12) having a hook-shape section (12_(C)) on one end and a loop extension section (12 _(F)) on the other forhandling during the manufacturing process. FIG. 1( f) shows the filamentassembly (12) being self-heated by the passage of electric current whileflushing the surrounding tube (10) with an inert gas containinghydrogen. This step in the process removes oxygen contamination fromwithin the confines of the light source body (10) and crystallizes thefilament (12 _(A)) itself. By applying direct current to the filamentpositioned so that magnetic forces counter balance the force of gravityon the filament, the crystal structure of the filament may be set sothat filament sag is avoided. FIG. 1( h) shows the filament tube'smidportion (10 _(A)) being blown into a mold (30) for precisedimensional control. FIGS. 1( m) and 1(n) show liquid nitrogen (46)being used to condense a gas filling in the central portion (10 a) whilea torch (20) “shrink seals” the quartz body (10) around the foil sealingmembers (48, 50). The quartz shrinks without excessive heat becausecondensing the fill gas reduces the internal pressure of the body belowatmospheric pressure. FIGS. 2( a)-2(l) and 3(a)-3(k) show the pump flushprocess implemented vertically for filament tubes and arc tubes,respectively. Minor differences from the horizontal flush processinclude straight ended lead wires handled by rods (72, 74) in anunspecified manner. Especially in the vertical process, the filamentassembly (12) or electrodes (92) are held in place by first and secondseal members abutting up against and respectively occupying the firstand second neck portions of the tube body, such that bent edges of thefoils (e.g., 12 _(D, 12) _(G)) serve as springs to position and maintainthe assembly (e.g., 12) on the central axis of the light source body.The seal members (12 _(D, 12) _(G, 92) _(B, 94) _(B)) may be of the typedescribed in U.S. Pat. No. 4,254,356 of Karikas, (further describedhereinbelow). In preparation for mounting a finished filament tube orarc tube in an outer envelope, ends of the tube are removed by diamondsaw cutting or scoring and snapping, thereby exposing a suitable lengthof the inlead wire extending beyond each end of the tube. As illustratedin FIGS. 6-10, the exposed lead wires are attached to a crossed lamplead wire on at least one end, and where appropriate, to the base eyeletat the other end to provide a simplified mount structure.

U.S. Pat. No. 4,254,356 (Karikas; 1981), incorporated by referenceherein, discloses inleads having a foil portion which is stiffened byreversely folded lateral edges, i.e., bent in opposite directions out ofthe medial plane. In making a discharge lamp, the electrode-inleadassembly is self-centering as a result of making the overall width ofthe foil portion and its reversely folded edges exceed slightly theinternal diameter of the quartz tube or neck. The inlead assembly (1)comprises a one-piece molybdenum wire portion (2, 3) wherein the centralportion (4) is foliated by longitudinal rolling to a thickness of about0.0009″ at the center. Karikas further teaches that the foliated portion(4) may also be produced by cross rolling and by swaging or hammering ofthe original wire, or may also use a composite foil comprising a cutlength of molybdenum foil to one end of which is welded a molybdenumwire and to the other end a tungsten wire. No further details areprovided about the proposed hammering process, and the present inventoris not aware of any practical mass production implementations of afoliation-by-hammering process in the lamp-making industry.

It is an overall object of the present invention to significantly reducethe manufacturing cost of high-efficacy light sources, particularlythose intended for household use, and more particularly thoseincorporating incandescent filament tubes contained within a protectiveouter envelope. Accordingly, it is an object to effectively eliminatethe likelihood of non-passive failure for filament tubes in lamps madeaccording to the invention. Accordingly, it is an object to mass-produceinexpensive filament tube envelopes. Accordingly, it is an object tomass-produce inexpensive foil/leadwire assemblies. Accordingly, it is anobject to simplify leadwire-to-filament assembly and the handling ofsaid assembly. Accordingly, it is an object to improve manufacturingefficiency for the flush-fill process. Accordingly, it is an object toimprove the mounting of filament tubes within an outer envelope. Othersubsidiary objects may become evident from the foregoing specificationof the present invention.

A further object of the invention is to utilize suitable features of theinventive filament tubes in order to cost-reduce double ended arc tubelamp manufacturing.

BRIEF SUMMARY OF THE INVENTION

According to the invention a process is disclosed for manufacturing alight source body, the body comprising a central tipless bulb having afirst outside diameter and the body being bookended by two diametricallyopposed transitional portions each necking down to a tubular necked-inportion having a second outside diameter smaller than the first outsidediameter; the process comprising the steps of: providing a length oftubing having an outside diameter no less than the first outsidediameter; forming a stretched-out portion of the tubing having thesecond outside diameter by heating the tubing while placing the tubingin tension; moving to keep the heating constantly centered in thestretched-out portion; cutting the stretched-out portion to form twonecked-in portions: one for a right end of a first light source body,and one for a left end of a second light source body; and advancing thetubing such that the forming, moving, and cutting steps can be repeatedto form a right end necked-in portion for the second light source body,thereby completing formation of the second light source body.

According to the invention, the process further comprises the step ofheating with a shaped burner for forming the transitional portions suchthat each has a shape with a smooth contour, smoothly transitioningbetween the first outside diameter and the second outside diameter.

According to the invention, the process further comprises the step ofcontrolling the heating and tension such that each transitional portionhas a wall thickness that smoothly varies from a first wall thicknessequal to a tubing wall thickness, to a second wall thickness equal to adifferent necked-in wall thickness.

According to the invention, the process further comprises the step ofproviding a controller for maintaining consistency, precision andrepeatability such that the shape and dimensions of each bulb, eachtransitional portion, and each necked-in portion are substantiallyduplicated or mirrored by the shape and dimensions of every other bulb,transitional portion, and necked-in portion, respectively.

According to the invention, the process further comprises the step ofproviding a controller for cyclically repeating the successive processsteps of forming, moving, cutting, and advancing in order to form aplurality of light source bodies in succession from a single length oftubing.

According to the invention, the process further comprises the step ofautomating to provide new lengths of tubing as needed, and to removecompleted light source bodies.

According to the invention, the cutting step of the process comprisesthe steps of: forming a cusped maria in the stretched-out portion; andcutting the tubing by initiating a crack along the line of a cusp of thecusped maria. Furthermore, the forming step of the process comprises thesteps of: heating a relatively narrow cylindrical band of thestretched-out portion; halting the heating as soon as the tubing in atleast the longitudinal center of the cylindrical band becomes plastic;and applying a longitudinal compression force to the tubing while thecylindrical band cools below the glass transition temperature, therebyforming a cusped maria in the cylindrical band. Preferably, the processfurther comprises the step of controlling the forming step such that theresulting cusped maria comprises two substantially duplicate bulged-outportions that join to form the vertex of a cusp.

According to the invention, light source bodies made by the disclosedprocess steps are themselves inventive.

According to the invention, another aspect of the process is disclosedfor manufacturing a light source body, the body comprising a centraltipless bulb having a first outside diameter that is bookended by twodiametrically opposed tubular portions; the process comprising the stepsof: providing a length of tubing having an outside diameter no less thanthe first outside diameter; determining a leg portion of the tubing thatextends between a first bulb and a second bulb; and cutting the legportion by the steps of: forming a cusped maria in the leg portion;providing control such that the resulting cusped maria comprises twosubstantially duplicate bulged-out portions that join to form the vertexof a cusp; and initiating a crack along the line of the cusp.

According to the invention, the cutting step of the process comprisesthe steps of: heating a relatively narrow cylindrical band of the legportion; halting the heating as soon as the tubing in at least thelongitudinal center of the cylindrical band becomes plastic; andapplying a longitudinal compression force to the tubing while thecylindrical band cools below the glass transition temperature, therebyforming the cusped maria in the cylindrical band.

According to the invention, the process further comprises the step ofproviding a controller for maintaining consistency, precision andrepeatability such that the shape and dimensions of each bulb, eachtubular portion, each cut, and each bulged-out portion are substantiallyduplicated or mirrored by the shape and dimensions of every other bulb,tubular portion, and bulged-out portion, respectively.

According to the invention, the process further comprises the steps of(after the cutting step): removing a completed light source body thatincludes the first bulb; advancing the tubing such that the determiningstep can be repeated on the other side of the second bulb to form asecond leg portion; cutting the second leg portion by following thesteps of either the cusped maria cut-off method, or by following thesteps of any non-maria cut-off method; and removing a second completedlight source body that includes the second bulb wherein the second lightsource body optionally has symmetrical bulged ends on both tubularportions or has one bulged end and one non-bulged end as determined bythe selection of cut-off method. Preferably the process furthercomprises the step of providing a controller for cyclically repeatingthe successive process steps of a first determining step, a firstcutting step, a first removing step, the advancing step, a seconddetermining step, a second cutting step, and a second removing step inorder to form a plurality of light source bodies in succession from asingle length of tubing.

According to the invention, light source bodies made by the disclosedprocess steps are themselves inventive.

According to the invention, a process for manufacturing a light sourcebody is disclosed, the body comprising a central bulb having a firstoutside diameter, and a tubular leg extending therefrom; the processcomprising the steps of: providing a length of tubing having an outsidediameter no less than the first outside diameter; determining a legportion of the tubing that extends from a bulb portion of the tubing;and cutting the leg portion by the steps of: forming a cusped maria inthe leg portion; providing control such that the resulting cusped mariacomprises two substantially duplicate bulged-out portions that join toform the vertex of a cusp; and initiating a crack along the line of thecusp; thereby forming a bulged end at the cutoff end.

According to the invention, light source bodies made by these disclosedprocess steps are themselves inventive.

Other objects, features and advantages of the invention will becomeapparent in light of the following description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made in detail to preferred embodiments of theinvention, examples of which are illustrated in the accompanying drawingfigures. The figures are intended to be illustrative, not limiting.Although the invention is generally described in the context of thesepreferred embodiments, it should be understood that it is not intendedto limit the spirit and scope of the invention to these particularembodiments.

Certain elements in selected ones of the drawings may be illustratednot-to-scale, for illustrative clarity. The cross-sectional views, ifany, presented herein may be in the form of “slices”, or “near-sighted”cross-sectional views, omitting certain background lines which wouldotherwise be visible in a true cross-sectional view, for illustrativeclarity.

Elements of the figures can be numbered such that similar (includingidentical) elements may be referred to with similar numbers in a singledrawing. For example, each of a plurality of elements collectivelyreferred to as 199 may be referred to individually as 199 a, 199 b, 199c, etc. Alternatively, a single element (e.g., shaft 391) may havemultiple parts (e.g., shaft inside end 391 a, shaft outside end 391 b).Or, related but modified elements may have the same number but aredistinguished by primes. For example, 109, 109′, and 109″ are threedifferent elements which are similar or related in some way, but havesignificant modifications, e.g., a tire 109 having a static imbalanceversus a different tire 109′ of the same design, but having a coupleimbalance. Such relationships, if any, between similar elements in thesame or different figures will become apparent throughout thespecification, including, if applicable, in the claims and abstract.

The structure, operation, and advantages of the present preferredembodiment of the invention will become further apparent uponconsideration of the following description taken in conjunction with theaccompanying drawings, wherein:

FIG. 1A is a filament tube light source assembly in process, accordingto the prior art;

FIG. 1B is a lamp assembly, according to the prior art;

FIGS. 2A-2E illustrate a process for manufacturing double ended, tiplessbodies for light sources as practiced on a lathe, according to theinvention;

FIG. 2A is a side view of a working end of tubing stock in the lathe,according to the invention;

FIG. 2B is a side view of the tubing being heated by a shaped burner,according to the invention;

FIG. 2C is a side view of a necked-in portion of the tubing being heatedby a narrow-flame burner, according to the invention;

FIG. 2D is a side view of a cusped maria formed in the necked-in portionof the tubing, according to the invention;

FIG. 2E is a side view of a completed body cut off of a remainingportion working end of the tubing, according to the invention;

FIG. 2F is a side view of two completed bodies cut off of a remainingportion working end of the tubing, made by alternate process embodimentsaccording to the invention;

FIG. 3 is a side view of a lead processing line for implementing afoliated lead manufacturing process, according to the invention;

FIG. 4A is a cross-sectional view, taken along the line 4A-4A of FIG. 3,of a wire that is positioned between working faces of hammers forfoliating the wire in a hammering stage of the foliated leadmanufacturing process, according to the invention;

FIG. 4B is a cross-sectional view, taken along the line 5B-5B of FIG.5A, shading omitted for clarity, of idealized (flattened) profiles ofthe wire as it progresses from an un-hammered wire down to an N-blowfoil in the hammering stage of the foliated lead manufacturing process,according to the invention;

FIG. 5A is a top view of a foil resulting from the hammering stage ofthe foliated lead manufacturing process, according to the invention;

FIG. 5B is a cross-sectional view, taken along the line 5B-5B of FIG.5A, of the foil resulting from the hammering stage of the foliated leadmanufacturing process, according to the invention;

FIG. 6A is a top view of a straightened foil resulting from a foilstraightening process of the foliated lead manufacturing process,according to the invention;

FIG. 6B is a cross-sectional view, taken along the line 6B-6B of FIG.6A, of the straightened foil resulting from the foil straighteningprocess of the foliated lead manufacturing process, according to theinvention;

FIG. 7A is a top view of wire, foliated according to the invention, thatis passing through first and second etching baths in a foil etchingstage of the foliated lead manufacturing process, according to theinvention;

FIG. 7B is an end view of a grommet seal for allowing passage of thefoliated wire through the etching baths of FIG. 7A, according to theinvention;

FIG. 8A is a perspective view of a wire cutter, according to theinvention;

FIG. 8B is a side view of a portion of wire having a straight cut endwith double-sided spurs resulting from a cutting process, according tothe invention;

FIG. 8C is an edge view of a straight or angled cut end resulting fromthe cutting process, according to the invention;

FIG. 8D is a side view of a portion of wire having an angled cut endwith a one-sided spur resulting from the cutting process, according tothe invention;

FIG. 8E is a top view of a one-piece foliated lead that results from apreferred embodiment of the lead manufacturing process implemented onthe lead processing line of FIG. 3, according to the invention;

FIGS. 9A-9C illustrate a process for manufacturing light source filamentassemblies, according to the invention;

FIG. 9A is a side view of a primary coil comprising a filament wire thatis wound on a primary mandrel, according to the invention;

FIG. 9B is a side view of a coiled coil filament being assembled withfirst and second foliated leads (portions visible), according to theinvention;

FIG. 9C, is a full side view of a completed filament assembly, accordingto the invention;

FIGS. 10A-12C and FIGS. 15A-15B illustrate preferred embodiments of alight source finishing process for manufacturing light sources,according to the invention;

FIG. 10A is a cross-sectional view of a finishing head, with thefilament assembly of FIG. 9C (not cross-sectioned) held in a collet ofthe finishing head, and with clamshells hingedly opened downward,according to the invention;

FIG. 10B is a cross-sectional view of a finishing stand comprising thecolleted top finishing head of FIG. 10A holding the filament assembly ofFIG. 9C (not cross-sectioned), and a colletless bottom finishing head,with the light source body (not shaded) of FIG. 2E sealingly held byclosed clamshells of both finishing heads, according to the invention;

FIG. 10C is a view of the finishing stand of FIG. 10B illustrating astep of the light source finishing process comprising making a firstseal of the body around a foliated lead of the filament assembly,according to the invention;

FIG. 10D is a view of the finishing stand of FIG. 10B illustrating astep of the light source finishing process comprising freezing fill gasinto the body and making a second seal of the body around a foliatedlead of the filament assembly, according to the invention;

FIG. 10E is a side, foil-edge view of a finished filament tube lightsource, according to the invention;

FIG. 10F is a side view, rotated 90° from the view of FIG. 10E, of afinished filament tube light source, according to the invention;

FIG. 11A is a top view of the collet of the colleted finishing head ofFIG. 10A, according to the invention;

FIG. 11B is a cross-sectional view, taken along the line 11B-11B of FIG.11A, of the collet of FIGS. 10A and 11A, showing portions of thefinishing head in which the collet is mounted, according to theinvention;

FIG. 11C is a top view of clamshells hingedly connected to a frame,according to the invention;

FIG. 12A is a cross-sectional view of a bulged end of a light sourcebody (not shaded) being loaded into a finishing head for which relevantportions are shown including an inner tube and clamshells, according tothe invention;

FIG. 12B is the finishing head portions and bulged end of FIG. 12Ashowing the bulged end being laterally centered by interacting with theinner tube, according to the invention;

FIG. 12C is the finishing head portions and bulged end of FIG. 12Bshowing the bulged end being coaxially aligned with the inner tube bythe closed clamshells, according to the invention;

FIG. 13A is a side view of an embodiment of a lamp wherein two filamenttube light sources are mounted in a general service incandescent lamp,according to the invention;

FIG. 13B is a side view, with an outer envelope shown in cross-section,of an embodiment of a lamp wherein one arc tube light source is mountedin a sealed beam headlamp, according to the invention;

FIG. 14 is a side view, with body material shown in cross-section, of abulged end of a light source body illustrating an electrical supportconnection to an outer lead wire of the light source, according to theinvention;

FIG. 15A is a cross-sectional view of a finishing stand comprising acolleted top finishing head holding a first electrode assembly (notcross-sectioned), and a colleted bottom finishing head holding a secondelectrode assembly (not cross-sectioned), with the light source body(not shaded) of FIG. 2E sealingly held by closed clamshells of bothfinishing heads, according to the invention; and

FIG. 15B is a side view of a finished arc tube light source, accordingto the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention, described hereinbelow in preferred embodiments,comprises manufacturing process steps that improve upon prior artprocesses for the manufacturing of light sources (both filament tube andarc tube), and lamps employing said light sources, generally by mountingthe light source within an outer envelope of a lamp. The improvedmanufacturing process steps result in improved subassemblies, improvedlight sources, and improved lamps, all of which are therefore intendedto be within the scope of the herein-disclosed invention(s). Many of theinventive improvements are directed toward cost-reducing light sourceproduction, especially for lamps that comprise one or preferably twolight sources mounted in an outer envelope. In particular, thecost-reduced improved processes can be utilized in the manufacturing ofa lamp such as the Gemini lamp wherein two filament tubes are mounted inan outer envelope to form a lamp that is affordable for common householdconsumer usage as a result of the inventive cost reduced manufacturingprocesses.

The preferred embodiments are described primarily for “filament tube”type light sources that use an incandescent tungsten filament, generallycoiled, and mounted within a tubular quartz (fused silica) envelope(light source body) to form a tipless double ended filament tube. Moreparticularly, the preferred embodiment light source is a 60 volt, 50watt halogen filament tube for mounting two-in-series in a lamp outerenvelope (e.g., lamp 400 in FIG. 13A) thereby creating a 100 W, 120Vhalogen lamp. The quartz tube is hermetically sealed around the filamentby means of the well known technique of using a thin molybdenum foil asthe electrical conductor passing through each seal area (the hermeticseal). Many of the same components and processes can be extended for usein the manufacturing of double ended, tipless “arc tube” type lightsources (e.g., metal vapor discharge lamps), and all such alternateembodiments—some examples of which are herein illustrated anddescribed—are intended to be within the scope of the present invention.The term “light source” is therefore intended to encompass anyelectrically-powered source of radiation (e.g., visible, infrared, etc.)that is manufacturable according to the present invention, particularlyfor incandescent filament light sources generally known as filamenttubes, and for arc-between-electrodes light sources generally known asarc tubes. Furthermore, herein-disclosed processes may have otherapplications, which are also intended to be within the scope of thepresent invention. For example, the foliated wire and it's manufacturingprocess could be used in other types of quartz sealing applications. Forexample, the light source bodies could be manufactured according to theinventive process as adapted to form glass or other non-quartz vitreousmaterial that can be, for example, sealed around wires instead of thedescribed foliated lead wires. Accordingly, the terms quartz and glassmay be used herein interchangeably, and are intended to be exemplaryembodiments of a broader class of vitreous materials, particularly thosethat are suitable for light source manufacturing.

As detailed in the background hereinabove, the prior art contains manyexamples of light sources comprising either filament tubes or arc tubesthat are housed in an outer envelope to form a complete lamp.Furthermore, various manufacturing processes for such lamps aredescribed, e.g., by the Ahlgren '932 patent. By way of reference, FIGS.1A and 1B show prior art filament tube and lamp assemblies, e.g., asdescribed in the Ahlgren '932 patent (part numbering modified). FIG. 1Ashows a hollow tubular light source body 1010 held in a head 1016 of ahorizontal glass lathe for further processing. A filament assembly 1012is provided having a filament 1012A with predetermined voltagecharacteristics, a first lead 1012B having one of its ends 1110 withattachment means shown as a hook-shape section 1012C and its other endconnected to a first foliated seal member 1012D which is furtherconnected to one end of the filament 1012A. A second lead 1012E havingone end 1112 with attachment means shown as a loop extension section1012F and its other end connected to a second foliated seal member 1012Gwhich, in turn, is further connected to the other end of the filament1012A. Subsequent processing yields a finished filament tube lightsource 1100 that is shown in FIG. 1B as being mounted in a type of lampthat is a sealed beam headlamp 1170. The sealed beam headlamp 1170 has areflector 1172 and lens 1173 and a pair of ferrules 1174 and 1176located at the base of the reflector 1172. The ferrules 1174 and 1176are respectively connected to a pair of electrical terminals 1178 and1180. The filament 1012A of the light source 1100 is connected acrossthe pair of ferrules by first 1182 and second 1184 electrical supportwires that are electrically and mechanically connected to the first andsecond lead ends 1110 and 1112, respectively. During filament tubeprocessing, the attachment means 1012C, 1012F have been cut off, and thebody 1010 has been formed as shown in FIG. 1B. In particular, thefilament 1012A is centered in a blown-out portion 1118, and the body1010 has been sealed 1102, 1104 about the first and second seal members1012D, 1012G, respectively, wherein the sealing process is completedafter pumping, flushing, and filling the light source body 1010 with asuitable light source ingredient. The processing of the light source isaccomplished through the legs 1106, 1108 of the body 1010, therebyobviating the need for an extra exhaust tube and its tip-off. The priorart also discloses similarly-manufactured light sources that employopposed arc electrodes in place of the filament 1012A, thereby creatingan arc tube type of light source that can be similarly mounted in anouter envelope such as the reflector 1172 and lens 1173 to form a lamp.

Light Source Body Manufacturing

FIGS. 2A-2E show an improved process for manufacturing double ended,tipless bodies (e.g., body 22 in FIG. 2E) for light sources (e.g.,filament tubes, arc tubes). This process can be practiced on anysuitable glass lathe, and is preferably automated to both minimizemanufacturing cost, and to provide dimensional consistency from part topart. Furthermore, one or more of the suitable glass lathes can beincorporated as a portion of an assembly line, preferably automated,that makes light sources and lamps according to the invention. Thedescribed embodiment of the body manufacturing process is illustratedwith a horizontal glass lathe, although the horizontal orientation isnot intended to be limiting. However, it may be noted that making anend-to-end symmetric bulb would more difficult on a vertical lathe dueto unsymmetrical heat loss. The inventive body manufacturing processwill be seen to be a cycle that proceeds in order through stepsillustrated by FIG. 2A, followed by FIG. 2B, etc., through FIG. 2E whichis then cyclically followed by the step of FIG. 2A, and so on—therebysequentially manufacturing multiple light source bodies 22 from a singlelength of tubing stock material. FIGS. 2A-2E illustrate lathe-formedtubing in profile wherein it should be understood that the profileshapes (including contours and dimensions) are rotationally equivalentabout a longitudinal axis of the tubing.

FIG. 2A shows a headstock 6 of a glass lathe 4 (only relevant portionsof the lathe 4 are illustrated as needed in FIGS. 2A-2E). The collet ofthe headstock 6 is laterally and longitudinally fixed, but rotates atpredetermined speeds as required. The headstock collet 6 grips a lengthof hollow tubular vitreous material, e.g., 3×5 mm quartz tubing 10(nominally 3 millimeter inside diameter, 5 millimeter outside diameterD1, and thus a 1 millimeter wall thickness T1). Since multiple lightsource bodies 22 are to be formed from a single length of tubing 10, thelathe 4 is adapted to accommodate a suitable length dimension for asupply end 10 b of the tubing 10 extending to the right of the headstock6. To the left of the headstock 6 a working end 10 a of the tubing 10extends. In FIG. 2A the working end 10 a has been previously worked suchthat it comprises a transitional portion 12, a necked-in portion 14, anda bulged end 16. The illustration of FIG. 2A assumes that the workingend 10 a is the result of completing the step illustrated by FIG. 2E andremoving a light source body 22 completed in that step. It should beobvious that in the case of starting with a new length of tubing 10, thesteps of FIGS. 2B-2E must be carried out on a working end 10 a that doesnot have a transitional portion 12, a necked-in portion 14, and a bulgedend 16, in order to create these requisite portions for the nextimplementation of the step of FIG. 2A. Also obviously, the bodyresulting from this first process cycle will be undesirablysingle-ended, and is generally scrapped, although as an alternative itcould be turned around and joined to the non-bulged working end 10 a ofanother new length of tubing 10. A tailstock collet 8 (see FIG. 2B) willobviously need to be able to accommodate the diameter of the tubing 10as well as the diameter of the necked-in portion 14. It is alsoadvantageous to use collet jaws that have, for example, swivel pads inorder to accommodate tapered and/or skewed tubing profiles.

FIG. 2B shows a step wherein a tailstock collet 8 of the lathe 4 hasgripped the necked-in portion 14 of the working end 10 a and pulled itthrough a loosened headstock collet 6 to stop the bulged end 16 at afirst predetermined position 21 a, whereupon the headstock collet 6 isretightened, and the lathe 4 (by means of the headstock 6 and tailstock8) begins rotation of the tubing 10 at a predetermined rotational speed.A shaped burner 26 is positioned at a first burner position 23 a suchthat heat (e.g., from a flame 28) is applied to the working end 10 a ofthe tubing 10. The first burner position 23 a is selected to produce abody 22 of a desired overall length L (referring to FIG. 2E). The flame28 is preferably shaped by the shaped burner 26 to vary the amount ofheat produced by different portions of the flame 28, thereby heating thetubing 10 in a way that varies along the length of the tubing 10 in apredetermined pattern (shape). The shape of the flame 28 maycontinuously vary, but a simple example of flame shaping is presented inFIG. 2B wherein the flame 28 has a central low heat zone 28 b that issymmetrically bookended by two higher heat zones 28 a, 28 c. Immediatelyafter the flame 28 has heated the tubing 10 to a predeterminedtemperature above its softening point, the tailstock 8 is biased with acontrolled amount of a bias force F1 directed to the left, therebyplacing the tubing 10 in tension. In its simplest form, the bias forceF1 can be applied with a weight on cable and pulley arrangement. A moresophisticated method comprises, for example, a stepper motor with forcelimiting controlled to start stretching the tubing 10 at the appropriatetime. Preferably some form of controller 5 is provided to control force,timing, rate, and extent of the stretching induced in the heated regionof the tubing 10. The controller 5 (e.g., a programmable controller 5associated with the lathe 4) preferably also controls timing andpositioning of the shaped burner 26 such that the flame 28 is turned onand off, optionally varied in heat output and optionally controlledseparately in its heat zones 28 a, 28 b, 28 c. Further preferably, theshaped burner 26 is moved left in concert with the leftward movement ofthe bulged end 16, thereby constantly maintaining heat in the center ofa stretched-out (and therefore necked-in) portion 14′ of the tubing 10(refer to FIG. 2C). Alternatively, the headstock 6 and tailstock 8 maybe moved equal distances at the same rate in opposite directions. This,of course, requires a lathe with a longitudinally moveable headstock.

FIG. 2C shows a step that starts with the working end 10 a that has beenshaped by the process of the previous step of FIG. 2B. Preferably thelathe is still rotating the tubing 10 at a predetermined speed. Underthe influence of the bias force F1, the tubing 10 that was heated by theshaped burner 26 has been stretched to form the stretched-out portion14′ bookended by a left transitional portion 12 a and a righttransitional portion 12 b. A bulb 18 portion of the tubing 10, with theoriginal straight-sided outside diameter D1 and wall thickness T1,remains between the left transitional portion 12 a and a previoustransitional portion 12 c (12 in FIG. 2A that was formed in a previousprocess cycle). The flame heat zones 28 a, 28 b, 28 c of the shapedburner 26 have been adjusted to create a smooth contour for thetransitional portions 12 a, 12 b, and movement of the shaped burner 26can assure that the left transitional portion 12 a has substantially thesame contour as the right transitional portion 12 b. It should be notedthat the contour of the transitional portions 12 a, 12 b not onlylongitudinally varies smoothly in outside diameter, but optionally alsolongitudinally varies smoothly in wall thickness. Smooth variation isherein defined to include a monotonic variation from a first dimensionto a second, different dimension. With suitable process control, thetransitional portions 12 a, 12 b will smoothly transition between thetubing 10 outside diameter D1 and a smaller predetermined necked-indiameter D2; similarly the tubing 10 wall will smoothly transitionbetween a tubing 10 wall thickness T1 and a predetermined necked-in wallthickness T2 that is optionally smaller than the tubing wall thicknessT1. Preferably a necked-in portion inside diameter (D2−2*T2) isapproximately equal to, or slightly larger than a foil width Wf for asealing foil (e.g., foil 76 in FIG. 6B). It should also be noted thatthe controller 5 provides control that is consistent, precise andrepeatable from cycle to cycle such that the shape and dimensions of theprevious transitional portion 12 c are substantially duplicated ormirrored by the shape and dimensions of the left transitional portion 12a and the right transitional portion 12 b. The step of FIG. 2C proceedssuch that a first cooling time is allowed after removal of heat from theshaped burner 26 (e.g., the shaped burner 26 is moved away from thetubing 10). The first cooling time is sufficient to allow the tubing 10to cool at least below its glass transition temperature. Aftercompletion of the first cooling time, a narrow-flame burner 30 ispositioned at a second burner position 23 b selected such that heatingfrom a flame 32 of the narrow-flame burner 30 is applied to a relativelynarrow cylindrical band 24 of the rotating tubing 10, the band 24 beinglocated at a longitudinal center of the stretched-out portion 14′ (i.e.,at the second burner position 23 b). As soon as the tubing 10 in atleast the longitudinal center 23 b of the cylindrical band 24 becomesplastic, the narrow-flame burner 30 is turned off and/or removed and alongitudinal compressive force F2 is applied to the working end 10 a(e.g., the tailstock 8 is forced to the right) while the tubing 10 coolsdown through the glass transition temperature.

FIG. 2D shows a step that starts with the working end 10 a that has beenshaped by the process of the previous step of FIG. 2C. The compressiveforce F2 has been applied (e.g., by a spring, not shown) in a way thatrelatively quickly moved a previous bulged end 16 c (an instance of thebulged end 16 shown in FIGS. 2A, 2B, 2C) from the second predeterminedposition 21 b to a third predetermined position 21 c. It is known in theglass working arts that longitudinal compression applied to a heatedtube will produce a bulged-out region commonly called a “maria”. If thecompressive force is applied after the glass becomes plastic andcontinued while the glass cools down through the glass transitiontemperature, the center of the maria (where the glass is hottest) willbulge out the most and is likely to form a sharply cusped contour wherethe cooler and therefore stiffer glass on the left of the maria's centeressentially tangentially joins the cooler glass on the right of thecenter. A maria that is cusped this way would normally be considereddefective because it is very fragile, i.e., liable to easily crack alongthe cusp. According to the present invention, a relatively highlongitudinal compressive force F2 is applied to the working end 10 auntil after the heated band 24 of tubing 10 cools below the glasstransition temperature such that a cusped maria 20 is intentionallyformed comprising a cusp 19 (providing a fragile ring around the centerof the stretched-out portion 14′ of the working end 10 a), and on eitherside of the cusp 19 providing left and right bulged ends 16 b, 16 c,respectively. Each bulged end 16 comprises an end for the tubing 10 thatis flared out diametrically and has a rotationally symmetric profilesimilar to that of the bell of a bugle. After forming the cusped maria20, the lathe 4 continues to rotate until the tubing 10 has cooled atleast below the glass transition temperature, whereupon the lathe 4stops rotating. Either just before, or soon after the lathe 4 stopsrotating, the cusp 19 is caused to break by placing it in tension (alongitudinal break-off force F3), optionally assisted by tapping on theheadstock collet 6 with a hammer 2, thereby initiating a mild shock wavethat will cause a ring-off type of crack to occur along the line of thefragile cusp 19.

FIG. 2E shows a step that starts after the completion of the process ofthe previous step of FIG. 2D. The lathe 4 is no longer rotating, and thetailstock 8 has been moved to the left after the cusped maria 20 hasbeen wrung-off. As a result, the working end 10 a of the previous step(illustrated in FIG. 2D) has been separated into a completed body 22 anda remaining portion working end 10 a′. Preferably the lathe controller 5has controlled the formation of the cusped maria 20 such that theformation is repeatable from cycle to cycle, thus forming duplicate(identical though mirrored) shapes at both ends of each body 22 as wellas substantially duplicate overall shapes from body 22 to body 22. Inother words, the previous transitional portion 12 c is substantiallyduplicated or mirrored by the shape and dimensions of the lefttransitional portion 12 a and the right transitional portion 12 b; theprevious necked-in portion 14 c is substantially duplicated or mirroredby the shape and dimensions of the left necked-in portion 14 a and theright necked-in portion 14 b; and the previous bulged end 16 c issubstantially duplicated or mirrored by the shape and dimensions of theleft bulged end 16 a and the right bulged end 16 b. In terms ofdimensions, outside diameters D1, D2 and wall thicknesses T1, T2(defined hereinabove) are controlled to be substantially duplicated inevery relevant portion of every body 22 produced according to thepresent invention. Length dimensions, measured longitudinally along thetubing 10 and body 22, are illustrated in FIG. 2E and should likewise beunderstood to be controlled so as to be substantially duplicated inevery relevant portion of every body 22 produced according to thepresent invention. The body 22 has a body length L that is subdividedinto two bulged end lengths LB1, LB2; two necked-in portion lengths LN1,LN2; two transitional portion lengths LT1, LT2; and one bulb length LB.The corresponding lengths in the remaining portion working end 10 a′have a right bulged end length LB3; a right necked-in portion lengthLN3; and a right transitional portion length LT3. Suitable control bythe controller 5 will cause the bulged end lengths to be substantiallyequal to each other (LB1=LB2=LB3); the necked-in portion lengths to besubstantially equal to each other (LN1=LN2=LN3); and the transitionalportion lengths to be substantially equal to each other (LT1=LT2=LT3).Similarly, the body length L and the bulb length LB will besubstantially equal to their corresponding lengths in all bodies 22 madeaccording to the present invention.

To complete the step of FIG. 2E, the tailstock collet 8 is opened andthe body 22 is removed for further light source assembly processes. Forexample, the body 22 could be ejected or otherwise caused to fall intoan accumulation tray (not shown). For example, a mechanical transfercould grip the body 22, remove it from the tailstock 8, and transfer thebody 22 for further processing. Following removal of the body 22, theprocess cyclically proceeds to the step of FIG. 2A, wherein theremaining portion working end 10 a′ becomes the new working end 10 a forthe process step of FIG. 2A. Similarly, the right bulged end 16 b, theright necked-in portion 14 b, and the right transitional portion 12 bbecome the new bulged end 16, necked-in portion 14, and transitionalportion 12, respectively.

It can be seen that the light source body 22 formed by theabove-described inventive process is a tipless double ended body formedwithout the complication and expense of blowing out into a mold or usinga cutoff saw/torch/laser/etceteras. As will be seen in the descriptionhereinbelow, the bulged ends 16 a, 16 c (collectively referred to as 16)not only provide a simple means of cutoff, but also provide advantagesin a finishing (e.g., flush/fill) process and in mounting of the lightsource in a lamp. The bulb portion 18 can be of any desired bulb lengthLB, including the limiting case wherein the transitional portions 12 a,12 c (collectively referred to as 12) adjoin each other causing astraight sided bulb length LB of zero, thereby forming a smoothlyrounded center for the body 22 similar to mold-blown bulb contours ofthe prior art. Such a body 22 with a rounded center may be desired for asmall arc tube, for example. If the body 22 is formed with the optionalvariation in wall thickness (see FIG. 2C), then several possibleadvantages ensue. Less tubing 10 is utilized in each body 22. Thenecked-in portions 14 a, 14 c (collectively referred to as 14) will beless massive, and therefore will store less heat in an operating lightsource. In a filament tube wherein an incandescent filament is mountedin the body 22 (as described hereinbelow), the transitional portions 12can be shaped, thinned, and positioned relative to the ends of thefilament such that the body 22 is substantially isothermal at leastaround the enclosed volume of the light source during operation of thefilament tube light source.

A further advantage of the inventive bulged ends 16 is the ability touse them for making a simple connection to a blow pipe in manufacturingprocesses wherein it is desired to blow out the bulb 18 (e.g., blowinginto a mold). As shown, for example, in FIG. 12B, a relatively airtightconnection between a tube (e.g., tube 170) and the bulged end 16 can bemade simply by pushing the tube (e.g., 170) into the bulged end 16, evenif the tube (e.g., 170) is slightly off-axis relative to the body 22.Furthermore, a cut off single-bulged working end 10 a could be turnedaround and joined to the non-bulged working end 10 a of a new length oftubing 10, thereby providing a bulged end 16 for making a blowingconnection for the first body 22 being formed at the working end of anew length of tubing 10.

FIG. 2F illustrates several features of light source bodies produced bypossible alternate embodiments of the present inventive process. A firstalternate body 922 a and a second alternate body 922 b (produced insequence after the first alternate body 922 a) are shown after being cutoff to leave a remaining portion working end 910 a′ that is still heldby the headstock 6 of the lathe 4. Two different cutoff methods are usedin alternating sequence for successive alternate bodies 922 a, 922 b.The cusped maria process, described hereinabove, has been used to createleft and right alternate bulged ends 916 a, 916 b where the firstalternate body 922 a has been cut apart from the second alternate body922 b in a second cutoff 915 b. However, a first cutoff 915 a and athird cutoff 915 c were made using a method other than the inventivecusped maria process (a non-maria cutoff method) to create non-bulgedends 917, collectively referring to a previous non-bulged end 917 c atthe first cutoff 915 a, plus a left non-bulged end 917 a and a rightnon-bulged end 917 b at the third cutoff 915 c. The non-maria cutoffmethod used for the alternate embodiment illustrated in FIG. 2F can be,for example, a known method employing a cut-off saw. By alternatingcutoff methods, it can be seen that each of the alternate bodies 922 a,922 b will have one bulged end (e.g., 916 a or 916 b) and one non-bulgedend (e.g., 917 c or 917 a).

FIG. 2F also illustrates another simplification of the inventive processwhereby the necked-in portions (e.g., 14 a, 14 c for the body 22 in FIG.2E) are omitted from the body manufacturing process. For example, thefirst alternate body 922 a has an alternate bulb 918 longitudinallycentered in the overall body length L, having a bulb length LB and abulb diameter equal to the tubing outside diameter D1. The alternatebulb 918 is bookended by diametrically opposed tubular portions: a lefttubular portion 914 a having a left tubular portion length LL1 and aleft tubular portion diameter equal to the tubing outside diameter D1;and a right tubular portion 914 b having a right tubular portion lengthLL2 and a right tubular portion diameter equal to the tubing outsidediameter D1 (except for the bulged end 916 a). The tubular portions 914a, 914 b in this example have equal lengths (i.e., LL1=LL2). Later lightsource manufacturing steps include sealing the tubular portions 914 a,914 b around lead wires and it should be noted that shrink sealing, forexample, will neck in part of each tubular portion 914 a, 914 b, therebyfurther defining the shape and dimensions of the alternate bulb 918.

Lead Manufacturing

FIGS. 3-8E show an improved process for manufacturing one piece foliatedleads (e.g., foliated lead 74 in FIG. 8E) for sealing in light sources(e.g., filament tubes, arc tubes). This process is preferably automated(e.g., using a lead processing line 40 as shown in FIG. 3) to bothminimize manufacturing cost, and to provide dimensional consistency frompart to part. Furthermore, one or more of the lead processing lines 40can be incorporated as a portion of an assembly line, preferablyautomated, that makes light sources and lamps according to theinvention.

FIG. 3 shows a preferred embodiment of the inventive lead manufacturingprocess, exemplified by the lead processing line 40, which has severalinventive features as detailed in FIGS. 4A-8E, described hereinbelow.The lead processing line 40 starts on the left with a wire supply spool44 of wire 42, processes the wire 42 into a foliated wire 43 by creatinga spaced string of foils 76, and then finishes on the right bysequentially cutting completed one piece foliated leads 74 off the endof the foliated wire 43 (for convenience in the foregoing discussion,the terms “wire 42”, and “foliated wire 43” may be used interchangeablyand each term should be understood to include the other term wherelogically appropriate since both terms refer to the same wire 42 beingprocessed and advanced through the lead manufacturing process). The wire42 is preferably molybdenum wire suitable for sealing and having thesame diameter (e.g., 0.007″) as a primary mandrel (e.g., 106 in FIG. 9A)for a filament (e.g., 102 in FIG. 9B) of the filament tube type of lightsource that will be made using the foliated lead 74. Alternatively forarc tube light sources, the wire 42 is molybdenum wire that is suitablefor sealing and for making into an arc electrode (e.g., first and secondelectrodes 306, 308 in FIG. 15A). Further alternatively for arc tubelight sources, the electrode (e.g., 306, 308) can be separately made(e.g., from tungsten wires), and subsequently attached (e.g., buttwelded) to the foliated lead 74 that is produced by the leadmanufacturing process described herein.

The spool 44 incorporates suitable tensioning devices (e.g., spool brake45) and wire guiding capabilities (not shown). The wire 42 is advancedthrough the lead processing line 40 by a wire advancing device embodiedhere as an advancing gripper 56 combined with a stationary gripper 58such that the foliated wire 43 is held by the stationary gripper 58while the advancing gripper 56 with open jaws moves to the left, and thefoliated wire 43 is advanced to the right by the advancing gripper 56with closed jaws while the stationary gripper 58 has open jaws. Theadvancing gripper 56 (e.g., under control of a stepper system) is alsoused in combination with the spool brake 45 to function as a tensioningdevice that provides tension and movement for accommodating elongationof the wire 42 as described hereinbelow. The grippers 56, 58 have jawshapes, and are positioned, such that the foils 76 are not damaged bythe gripping and advancing operations (e.g., the foils 76 are nevertouched by the grippers 56, 58).

The lead processing line 40 produces a new foliated lead 74 every cycle,wherein the machine cycle comprises: advancing the wire 42, andprocessing portions of the wire 42 simultaneously in each of severalstages of the lead manufacturing process. The wire 42 is advanced by a“step” distance selected to produce a uniform desired foil spacing FS(see FIG. 7A). It will be seen that the selected amount of initialadvancement is slightly less than the foil spacing FS in order toaccommodate elongation of the wire 42 that occurs in some of the stages.Thus during each machine cycle the wire 42 is advanced one step equalingthe foil spacing FS, but comprised of an initial advancement distanceplus the small amount of elongation that occurs during the cycle. Themachine cycle timing (per completed foliated lead 74) is determined bythe most time-consuming stage of operation, that being a hammering stagethat has been proven at a rate of at least 90 per minute, i.e., a cycletime of 0.67 seconds. The stages of the lead manufacturing process willnow be presented in sequential order.

Referring to FIGS. 3, 4A and 4B, a first stage of the lead manufacturingprocess is foil hammering wherein a portion of the wire 42 is hammeredinto a thin, sharp-edged sealing foil between a top hammer 46 a and abottom hammer 46 b driven by a hammering drive 47. The hammers 46 a, 46b (collectively referred to as hammers 46) are cemented carbide and haveidentically shaped working surfaces: a working face 92 on a truncatedconical frustum 90. The working face 92 has a slightly convex surfacecentered on an axis of revolution AR, and is rounded at an edge 94 whereit transitions to the frustum 90. For example, the working face 92 hasan oblate spheroid surface with a major-to-minor axis ratio of about 100to 1, wherein an axis of revolution AR lies along the minor axis of theoblate spheroid, and the rounded transition edge 94 ends at the frustum90 along the major axis of the oblate spheroid. The hammers 46 arearranged such that the working faces 92 are aligned to be centered on acommon axis of revolution AR with opposed working faces 92 that aremirror images of each other; and furthermore such that hammering motionis along the common axis of revolution AR. The working face 92 has adiameter DWF that is selected to determine a suitable foil length Lf andfoil width Wf (see FIGS. 6A-6B). For example, the working face diameterDWF is 0.125″, and can be used to hammer a molybdenum wire 42 having a0.007″ wire diameter Dw into a foil having a foil length Lf ofapproximately one eighth of an inch and a foil width Wf of slightly less(e.g., approximately 0.1″). The wire 42 is advanced between the workingfaces 92 of the hammers 46 by an amount selected to produce a uniformdesired foil spacing FS (see FIG. 7A) and stops with the wire 42positioned along a diameter of the working face 92 (i.e., crossing thecentral, highest point of the working face 92, orthogonally crossing theaxis of rotation AR). The wire 42 is hammered between the working faces92 with a number N of blows in as rapid succession as possible. (It isbelieved that this will advantageously maximize the amount of heat inthe wire 42 that is produced by the hammering.) The number N of blows isexperimentally determined for a given wire material and diameter; e.g.,for the 0.007″ diameter molybdenum wire the number N has been determinedto be 10. An important feature of the process is that for a givenmagnitude of energy E provided in the first blow, each subsequent blowhas an energy that is at least linearly increased by the energymagnitude E over its preceding blow. For example: the first blow has anenergy magnitude of E; the second blow has an energy magnitude of 2×E (2times E); the third blow has an energy magnitude of 3×E; and so on tothe final Nth blow having an energy magnitude of N×E. The increasingenergy is necessary in order to produce a sharp-edged foil contour(e.g., foil edge 77); otherwise the foil will tend to flatten in themiddle or even doughnut without appreciably more stretching and thinningof the foil edges 77. The energy magnitude E along with the number ofblows N are experimentally determined for a given wire material anddiameter so as to produce a desired foil thickness Tf. For example, thefoil thickness Tf is 0.001″. It has been noted that the foil edges 77are thinned and sharpened by this wire flattening process. The resultingfoil edge 77 is easily etched to yield an even sharper razor edge thatis ideal for optimum sealing of the foil in vitreous material (e.g.,quartz).

Top and cross-sectional views of a foil 75 resulting from the hammeringstage are shown in FIGS. 5A and 5B, respectively. The resulting foil 75tends to be slightly cupped (although the illustration exaggerates thiseffect). FIG. 4B shows idealized cross-sectional views (shading omittedfor clarity) of the middle of the foil 75 after progressive hammerblows. The cross-section is taken as shown in FIG. 4A, at the pointwhere the wire 42 intersects the axis of revolution AR; for example,along the line 5B-5B of FIG. 5A, however for illustrative purposes it isidealized by showing the profile as straight rather than cupped as inFIG. 5B. The idealized profiles in FIG. 4B progress from an un-hammeredwire 42 a having a wire diameter (and foil thickness) Dw, down to anN-blow foil 42 f having the desired foil thickness Tf (as measured atit's center). For example, a 2-blow foil 42 b shows the foilcross-sectional profile after 2 hammer blows on the wire 42; a 4-blowfoil 42 c shows the foil cross-sectional profile after 4 hammer blows onthe wire 42; a 6-blow foil 42 d shows the foil cross-sectional profileafter 6 hammer blows on the wire 42; a 8-blow foil 42 e shows the foilcross-sectional profile after 8 hammer blows on the wire 42; a 10-blowfoil 42 f shows the foil cross-sectional profile after 10 hammer blowson the wire 42 (where N=10).

The idealized profiles in FIG. 4B are merely illustrative of onepossible scenario. Various cross-sectional shapes have been observed atvarious points in the hammering process including the following: Theprogression in cross-sectional shapes goes from round to wiener shapeafter the first blow, with the waist portion taking the shape of thehammer faces 92. As the blows increase in energy, the working faces 92themselves progressively compress. The overall foil 75 gets thinner, butthe center again becomes thicker relative to the edges, presumably dueto a hydrostatic “capturing” of the molybdenum such that the edgesalmost cease to flow. Cross-sectional shapes then progress fromelliptical to lenticular in nature. Toward the end of the process it maybe that the compressive forces over the whole active area are very high,but are higher in the center than at the edges of the working faces 92,thus producing the cupped effect when expansion occurs after relief ofthe pressure of the last blow. As the foil 75 gets thinner and thinnerit resists plastic flow more and more. Lengthwise elongation decreases,and with further blows beyond N, the extruded foil along the lengthcontinues to thin until it is too fragile to be useful.

Because of longitudinal pressure on the tapered surface of the wire 42where it transitions from the foil to the wire, the wire 42 tends toelongate even more than the foil width. During the hammering process thelead processing line 40 should provide a suitable bias force on the wire42 to prevent longitudinal rippling or folding of the foil; for examplethe advancing gripper 56 can advance further during hammering, or canincorporate a spring tensioner while the spool brake 45 resists.Preferably provisions are made to keep the hammers 46 centered in thefoil 75 to avoid a longitudinally asymmetric foil 75; for example thehammers 46 are advanced a predetermined amount after each hammer blow,or the spool brake 45 pulls the wire 42 backward a predetermined amountafter each hammer blow while the advancing gripper 56 pulls the wire 42forward an equal predetermined amount.

An exemplary reduction to practice (not specifically illustrated) of theinventive hammering process comprised a hammering drive 47 with thebottom hammer 46 b mounted on a massive, rigid base, and the top hammer46 a slidably mounted in a vertical guide channel. In lab tests, the tophammer 46 a was raised a height H and dropped for the first blow, raiseda height 2×H and dropped for the second blow, and so on until it wasraised a height 10×H for the final 10^(th) blow. Thus the energyprovided by the falling weight increased linearly for each blow inproportion to the height of the fall. In another reduction to practicetest, the top hammer 46 a was in turn hammered by a hammering drive 47comprising a swinging hammer attached to a leaf spring that was raisedagainst spring force by a constant-speed rotating cam wheelincorporating 12 cam steps. Each of the first ten cam steps raised andthen released the spring, but the eleventh and twelfth cam steps heldthe spring and the top hammer 46 a up slightly to allow advancing thewire 42. Each of the first ten cam steps raised the spring more than thepreceding cam step in a linear progression, thereby yielding a geometricprogression in hammering energy (proportional to the square of thespring raising distance, and therefore more than linear). It isanticipated that the inventive hammering process can be implemented withmany different forms of hammering drive 47 including, for example,hammering drives 47 that use electromagnetic/solenoidal force ratherthan the above-described exemplary mechanical methods.

Referring to FIGS. 3, and 5A-6B, a second stage of the leadmanufacturing process is a foil straightening stage that preferably alsoincludes flame etching of the foil. Foil straightening is desiredbecause the hammering process tends to produce a slightly cupped contourfor the foil 75 as shown in FIGS. 5A and 5B (cupping illustrativelyexaggerated). For example, a first face 84 a is concave while the other,second face 84 b, is convex. The cupped foil 75 is bistable(concave-convex), can angle the wire 42 on either side out ofcollinearity, and may not present the best shape for sealing. However,when straightened according to the invention, the cupped foil 75 becomesa straight foil 76 that has advantageous stiffening edges 77′. In thepreferred embodiment, heat for the second stage is provided by a burner48 having a flame 49 that is positioned for heating the cupped foil 75after the cupped foil 75 is advanced out of the hammers 46. The flame 49is long enough to accommodate movement of the cupped foil 75 as the wire42 and cupped foil 75 elongate during the cycle due to hammering andstraightening. The flame 49 is optionally extended, and furtheroptionally segmented, in order to heat a plurality of foils 75, 76 at aplurality of foil step locations in order to continue heating the foils75, 76 for a plurality of cycle times. Foil straightening isaccomplished by applying a tensile force on the wire 42 and thus on thecupped foil 75 (e.g., by means of the advancing gripper 56), preferablywhile heating the cupped foil 75. A side benefit of the inventive foilstraightening process is that the wire 42 can also be straightened, ifnecessary, by the same process. The foil 76 resulting from the foilstraightening process is shown in top and cross-sectional views in FIGS.6A and 6B, respectively. The elliptical dish shape of the cupped foil 75has been stretched flat on the two longitudinal ends, and in the foilmiddle. The sharp edges 77 have been stretch straightened out-of-roundand tend to curl around a longitudinal line to produce substantiallylongitudinally linear, curled edges 77′ that provide collinearity forinner lead wire 82 and outer lead wire 83, and bending stiffness for thefoil 76, and therefore for the foliated lead 74. Although the edges 77are stretched the most, the overall foil length also increases slightlyfrom a cupped foil length Lcf to a foil length Lf, both lengths beingmeasured between the two locations where the foil 75, 76 starts totransition from the foil thickness Tf to the wire diameter Dw. Thus theinventive straightening process provides a simplified, improved methodfor achieving many of the same benefits of prior art foil stiffeningmethods such as that disclosed in the Karikas '356 patent. The curlededges 77′ both generally curl toward the same foil face (e.g., firstface 84 a), therefore they do not exactly center the foliated lead 74 ina light source body (e.g., body 22) before sealing in the same way asthe bi-folded foils of Karikas. However, the inventor has determinedthat centering occurs anyway with the present foliated leads 74 when thebody 22 is sealed about the foil 76, and furthermore the foliated leads74 also provide desired alignment of the foliated lead 74 with thenecked-in portion 14 and therefore with the body 22.

A further advantage of the inventive foliated leads 74 made according tothe inventive hammering process is the shape of leading/trailing ends 88of the foil 76. The resulting tapered or at least rounded-off shape ofthe leading/trailing ends 88 is a feature of the inventively hammeredfoil 76 that eases threading of the foliated lead 74 into aclose-fitting tube (e.g., the necked-in portions 14 of the light sourcebody 22).

In the art of making light source sealing foil, it is known that thebest edge for sealing is obtained by etching a flattened metal strip,regardless of the method used for that flattening. Two methods for foiletching are chemical or electrochemical etching, and flame etching(using an oxidizing flame to burn away metal). A disadvantage of flameetching is that it leaves an oxide coating that may interfere withsealing. Therefore, a third stage of the lead manufacturing process is afoil etching stage preferably using an electrochemical etching processthat will also clean any oxide coating off of the foliated wire 43, andmay even etch more efficiently when the foliated wire 43 has beenoxidized previously. Therefore, an optional alternate embodiment of thelead manufacturing process uses an oxidizing flame for the flame 49 tocombine flame etching with foil straightening. Further alternateembodiments of the lead manufacturing process replace electrochemicaletching with an oxidizing flame 49 for flame etching followed bycleaning by, for example, heating in a reducing atmosphere such asforming gas.

The preferred embodiment of the lead processing line 40 incorporates anelectrochemical etching process for a third, foil etching stage of thelead manufacturing process. Referring to FIGS. 3, 7A and 7B the thirdstage comprises a first etching bath 50 a followed by a second etchingbath 50 b (collectively referred to as etching baths 50), followed by arinsing bath 52, and finally followed by a dryer 54. The first andsecond etching baths 50 a, 50 b are respectively filled to a first andsecond fluid level 86 a, 86 b with an electroetching fluid 53 a, 53 bcollectively referred to as electroetching fluid 53 (e.g., an alkalisuch as sodium hydroxide). In order to preclude possible damage to thefoils 76, the foliated wire 43 follows a conveyance path that passesstraight through the etching baths 50 and the rinsing bath 52 instead ofbeing redirected down into and up out of each bath by a typical seriesof rollers or pulleys. The straight-through conveyance path is enabledby passing the foliated wire 43 through relatively liquid-tight grommetseals 72 that are mounted within holes 51 below the fluid level 86 a, 86b in both longitudinal ends of each bath 50 a, 50 b, 52. The grommetseal 72 is made of a resilient material (e.g., rubber, plastic, etc.)having a slit 73 that flexes sufficiently to allow passage of thefoliated wire 43 through the grommet seal 72, but still holds the slit73 closed enough to prevent significant fluid loss leaking through fromthe bath 50 a, 50 b, 52. Leaked fluid can be replenished by capturing itand pumping it back into the bath 50 a, 50 b, 52, or simply byreplacement with fresh fluid, thereby maintaining constant causticconcentration. An exemplary grommet seal 72 was produced by using ashort length of soft rubber, thick walled tubing with a pinch-clamp.Compression by the pinch-clamp produced the slit 73 and theelectroetching fluid 53 provided an excellent lubricant. It is withinthe scope of the present invention to abut the ends of successive baths50 a, 50 b, 52 and to use a single grommet seal 72 between each pair ofabutted baths 50 a, 50 b, 52. Furthermore, said abutment should beherein construed to include combination of the abutted ends into asingle dividing wall. Alternatively, the single grommet seal 72 betweensuccessive baths 50 a, 50 b, 52 could be a short length of smalldiameter tubing, possibly pinched to form a slit 73, the tubingextending between the holes 51 in the ends of the successive baths 50 a,50 b, 52.

Chemical etching is enhanced by electrolysis using an inventive two-bathAC (alternating current) electrolysis method that doesn't require amechanical connection of electrical power to the foliated wire 43, againin order to avoid damage to the foliated wire 43, and also to increasereliability and efficiency. One pole of an AC electrolysis power supply66 is connected by a first supply wire 68 a to a first electrode 70 a inthe first etching bath 50 a, and the opposite pole of the electrolysispower supply 66 is connected by a second supply wire 68 b to a secondelectrode 70 b in the second etching bath 50 b. The circuit iscompleted, for example, by electrical current being conducted by ions inthe electroetching fluid 53 a in the first etching bath 50 a from thefirst electrode 70 a to the foliated wire 43 in the first etching bath50 a, the current then being conducted by the foliated wire 43 from thefirst etching bath 50 a to the second etching bath 50 b, the currentthen being conducted by ions in the electroetching fluid 53 b in thesecond etching bath 50 b from the foliated wire 43 in the second etchingbath 50 b to the second electrode 70 b. In the succeeding half cycle ofAC, the current flow is reversed. Electrolytic etching of the foliatedwire 43 alternates between the first and second etching baths 50 a, 50 bdepending upon the direction of current in the etching bath 50. A firstbath length BL1 and a second bath length BL2 are selected to provide atotal etching bath length (BL1+BL2) sufficient to allow enough machinecycle times for each foil 76 to be etched as desired while it stepsthrough the etching baths 50. The first and second etching bath lengthsBL1, BL2, respectively, are preferably approximately equal in order tobalance the current density in the two baths 50 a, 50 b. An advantage ofthe inventive two-bath etching method is that the current carriedbetween baths 50 a, 50 b by the foliated wire 43 can be relatively highbecause of the cooling provided by the electroetching fluid 53,especially when the baths 50 are connected by a single grommet seal 72,thereby preventing exposure of the foliated wire 43 to air between thebaths 50.

Referring to FIG. 3, after passing through the etching baths 50, thefoliated wire 43 (now etched) is passed straight through the rinsingbath 52. Other than inventively passing the foliated wire 43 through therinsing bath 52 by means of grommet seals 72 as described for theetching baths 50, the rinsing bath uses conventional means to rinseelectroetching residue from the foliated wire 43 (e.g., using de-ionizedwater). A length of the rinsing bath 52 is selected to allow enoughmachine cycle times for each foil 76 to be rinsed as desired while itsteps through the rinsing bath 52. After passing through the rinsingbath 52 the foliated wire 43 is passed through a conventional dryer 54(e.g., hot air) that is preferably non-oxidizing.

FIGS. 3 and 8A-8E illustrate a final, fourth stage of the leadmanufacturing process that comprises a cutting stage. After the foliatedwire 43 passes through the foil etching stage, the foliated wire 43 isadvanced by the advancing gripper 56 and pushed out through thestationary gripper 58 and a cutter 60. At a point during the machinecycle when the advancing gripper 56 is not moving, and the length offoliated wire 43 protruding beyond the blade edges 63 is sufficient toyield a predetermined foliated lead length Lfl after cutting, thestationary gripper 58 optionally closes to hold the foliated wire 43while the cutter 60 closes to cut a foliated lead 74 off the end of thefoliated wire 43. The newly manufactured foliated lead 74 is madeavailable for further light source manufacturing processes, optionallyby allowing it to fall into a collection tray 64; but preferably byusing a transfer 62 (e.g., vacuum head on swing arm) to hold thefoliated lead 74 as it is cut off and to then move it into thecollection tray 64 or on to a next portion of a light source assemblyline.

An inventive cutting process produces straight cut ends 78 a or angledcut ends 78 b (collectively referred to as cut ends 78) on the foliatedlead 74 that respectively have intentionally-formed double-sided spurs80 a, or a one-sided spur 80 b (80 a and 80 b being collectivelyreferred to as spurs 80). The spurs 80 protrude laterally beyond thediameter of the wire 42 that becomes a lead wire 82, 83 (e.g., the innerlead wire 82) of the foliated lead 74, and the spurs 80 are thenutilized to improve subsequent assembly and handling operations as willbe described hereinbelow. The cutter 60 has a top blade 59 a and abottom blade 59 b (collectively referred to as cutter blades 59) thatare preferably identically shaped with a blade edge 63 defined at thevertex of a left blade side 61 a and a right blade side 61 b(collectively referred to as blade sides 61). The cutter 60 has acentral plane CP, and the top blade 59 a is positioned above the bottomblade 59 b such that both blade edges 63 lie within the central planeCP. Furthermore, the cutter 60 has a configuration wherein cuttingmotion of the cutter 60 is such that the cutting blade edges 63 movesubstantially within the central plane CP, thereby bringing the bladeedges 63 together to cut the foliated wire 43. In general, the bestspurs 80 are produced by cutting with dull-edged (i.e., blunt) cuttingblade edges 63 such that the cutting process is one of essentially“mashing apart” the foliated wire 43 as with dull nippers. Preferablythe blade sides 61 are substantially straight and form a relativelybroadly sloped blade angle α at the vertex (blade edge 63), the bladeangle α being in the range of about 60°-120°, most preferably about 90°.Preferably the blade sides 61 a, 61 b are reflected across the centralplane CP, i.e., each is at an angle of α/2 from the central plane CP.The foliated wire 43 is positioned in the cutter 60 such that a wire 42portion at a predetermined distance from the nearest foil 76 (e.g., aninner lead length Lil) is between the blade edges 63. In a verticaldirection, the wire 42 is perpendicular to the central plane CP. In ahorizontal direction, the wire 42 is at a cut angle θ. FIGS. 8B and 8Cshow the straight cut end 78 a that results from cutting at a cut angleθ equal to about 90°. Because of the shape of the cutter blades 59 withrelatively broadly sloped blade sides 61, the round wire 42 is pinchedin, which causes displaced wire material to extrude outwards by aprotrusion distance of PD on each side (measured radially), therebycreating the double-sided spurs 80 a. FIGS. 8D and 8C show the angledcut end 78 b that results from cutting at a cut angle θ that is acute,preferably about 45°-75°, most preferably about 60°. Because of theshape of the cutter blades 59 with relatively broadly sloped blade sides61, the round wire 42 is pinched in, which causes displaced wirematerial to extrude outwards by a protrusion distance of PD (measuredradially), thereby creating the one-sided spur 80 b. In addition to theone-sided spur 80 b that protrudes laterally on the side of the acutecut angle θ, the other side of the angled cut end 78 b is rounded towardthe center of the wire 42, thereby creating a point 79 at the outermostend of the lead wire 82, 83. The angled cut end 78 is most preferred forthe present invention because it not only has the spur 80 but also thepoint 79, both of which provide advantages in subsequent assembly andhandling operations according to the invention as will be describedhereinbelow. Trials of the inventive cutting process using 0.007″diameter molybdenum wire 42 resulted in spurs 80 having a protrusiondistance PD of approximately 0.001″.

FIG. 8E shows the foliated lead 74 that results from a preferredembodiment of the inventive lead manufacturing process implemented onthe lead processing line 40. The foliated lead 74 has an overallfoliated lead length Lfl, is formed from one continuous piece ofmaterial (originally the wire 42), and comprises a single foil 76 (forsealing in a light source body, e.g., body 22) bookended by an outerlead wire 83 and an inner lead wire 82. The foil 76 has curled edges77′, a foil length Lf, and a foil width Wf. The outer lead wire 83 hasan outer lead length Lol and a diameter equal to the wire diameter Dw ofthe wire 42. The inner lead wire 82 has an inner lead length Lil and adiameter equal to the wire diameter Dw of the wire 42. Both lead wires82, 83 outwardly end in cut ends 78, preferably angled cut ends 78 bthat have a point 79 and a spur 80.

The lead processing line 40 has been described as a single, completemultistage line, but it should be recognized that the scope of theinvention is intended to include the use of individual stages of theline, possibly separated from other stages by means of collecting thefoliated wire 43, for example, on a reel of sufficient diameter topreclude introducing permanent bending or other damage to the foliatedwire 43; and then unreeling the foliated wire 43 from the reel tocontinue the lead processing elsewhere.

Filament Assembly

FIGS. 9A-9C show an improved process for manufacturing filamentassemblies (e.g., filament assembly 104 in FIG. 9C) for light sources(e.g., filament tubes, arc tubes) wherein two foliated leads 74 (firstfoliated lead 74 a and second foliated lead 74 b) are assembled togetherwith an incandescent lamp filament (e.g., filament 102) therebetween andprepared for assembly with a light source body (e.g., body 22). Thisprocess is preferably automated to minimize manufacturing cost, and toprovide dimensional consistency from part to part. Furthermore, one ormore filament assembly processes can be incorporated as a portion of anassembly line, preferably automated, that makes light sources and lampsaccording to the invention.

FIG. 9A shows a primary coil 100 comprising a filament wire 108 that iswound on a primary mandrel 106, preferably with periodically variedcoiling pitches P1, P2, P3, thereby creating a continuous length ofprimary coil 100 having a repeating sequence of: a first spud portion110 a, preferably followed by a first stretched-out portion 112 a,followed by an incandescent portion 114; and then preferably followed bya second stretched-out portion 112 b. The sequence repeats beginningwith a second spud portion 110 b. It should be noted that the spudportions 110 a, 110 b (collectively referred to as 110) are each cut inhalf when a filament 102 is created from the primary coil 100. Referringalso to FIG. 9B, the preferred embodiment of the present inventionincludes a 50 W (watt), 60 V (volt) filament 102 that utilizes a coiledcoil portion 115 for the incandescent part of the filament 102. Itshould be recognized that light sources according to the presentinvention may have other wattage/voltage combinations, and can beachieved, for example, with single coil filaments, and with or without astretched-out portion 112 a, 112 b (collectively referred to as 112).

For the preferred embodiment, the primary mandrel 106 is molybdenum wirehaving a mandrel diameter Dm (e.g., 0.007″), and the filament wire 108is tungsten filament wire having a filament wire diameter Dfw (e.g.,0.0025″). The incandescent portion 114 is the longest portion of theprimary coil 100, being long enough to accommodate the length offilament wire required for a particular voltage/wattage/life design. Thecoiled coil portion 115 has a coiled coil pitch P4, and a coiled coiloutside diameter Dcc (e.g., 0.042″) that are determined according toconventional design principles. An incandescent primary coil pitch P3 isalso determined according to conventional design principles. A spudportion pitch P1 is preferably equal to the incandescent primary coilpitch P3. A stretched-out portion pitch P2 is stretched as much aspossible to result in, for example, up to three lazy turns in astretched-out portion length Lst. The spud portion 110 has a spudportion length Lsp of approximately twice the length desired for aspudding operation to be described hereinbelow. If desired, thecontinuous length of primary coil 100 may be annealed on the primarymandrel 106 before secondary coiling.

The filament 102 is formed by: (a) extending a first leg 116 acomprising a first spud coil 111 a (being half of the first spud portion110 a) plus a first stretched-out leg 113 a; (b) secondary coiling,i.e., winding one incandescent portion 114 of the primary coil 100around a removable secondary mandrel (conventional, not shown) to formthe coiled coil 115; (c) extending a second leg 116 b comprising asecond stretched-out leg 113 a plus a second spud coil 111 a; (d)removing the secondary mandrel; (e) cutting the primary coil 100 in theapproximate middle of the second spud portion 110 b; and (f) dissolvingthe primary mandrel 106. Sintering of the coiled coil 115 may be doneaccording to conventional practice, e.g., between steps (e) and (f), orpossibly after the following optional step (g). An optional step (g)after dissolving the primary mandrel 106 is to further stretch andstraighten the first and second stretched-out portions 112 a, 112 b inorder to form first and second legs 116 a, 116 b that arealmost-straight single strands of filament wire 108 having astretched-out leg length Lst′ that may be significantly longer than thestretched-out portion length Lst of the primary coil 100. This optionalstep (g) can be used to create stretched-out legs 113 a, 113 b even whenthe stretched-out portions 112 of the primary coil 100 are not stretched(i.e., the stretched-out portion pitch P2 is equal to the incandescentprimary coil pitch P3). In step (e) each filament 102 is cut off an endof the continuous length of primary coil 100 by means of cutting theprimary coil 100 in the approximate longitudinal center of a spudportion 110, thereby creating filament spud coils 111 a, 111 b(collectively referred to as 111) that are approximately half the lengthof the spud portions (i.e., spud coil length Lsp′ is approximately halfof the spud portion length Lsp).

Referring to FIGS. 9B and 9C, the filament assembly 104 comprises afilament 102 that is assembled together with a first foliated lead 74 aand a second foliated lead 74 b. The first foliated lead 74 a has afirst inner lead 82 a, a first foil 76 a, and a first outer lead wire 83a. The second foliated lead 74 b has a second inner lead 82 b, a secondfoil 76 b, and a second outer lead wire 83 b. As described hereinabove,each of the foliated leads 74 has two cut ends 78, and each cut end 78has at least one spur 80, and preferably a point 79 (when the cut end 78is the preferred angled cut end 78 b). The foliated leads 74 are madeusing wire that becomes the inner lead wires 82 a, 82 b and has a wirediameter Dw. The inside diameter of the spud coils 111 is approximatelythe same dimension as the primary mandrel diameter Dm upon which theywere wound. For the preferred embodiment illustrated in FIG. 9B, thefirst inner lead wire 82 a of the first foliated lead 74 a is shown asit is being assembled with the filament 102, and the second inner leadwire 82 b of the second foliated lead 74 b is shown after beingassembled with the filament 102. The illustrated assembly isaccomplished by a spudding process wherein the cut end 78 of an innerlead wire 82 becomes a “spud” that is inserted into a tight fitting spudcoil at the end of a leg 116 of the filament 102. Although spudding isknown, the present invention provides an improved spudding process dueto inventive features of the inner lead wire 82. In particular, theinner lead wire outside diameter Dw is approximately the same as, orslightly more than, the spud coil inside diameter Dm; and the one ormore spurs 79 on the cut end 78 provide a lateral protrusion that servesas a screw thread such that the cut end 78 can be “screwed” into thespud coil 111 and the spur(s) 79 will thereafter hook onto a turn of thespud coil 111. Because of this hooking, it is not necessary to make theinner lead wire outside diameter Dw significantly larger than the spudcoil inside diameter Dm; and it is also not necessary to weld the spudcoil 111 to the inner lead wire 82. A further advantage accrues when thecut end 78 is the preferred angled cut end 78 b with a point 79, inwhich case the point 79 (which tends to be somewhat indented from theoutside diameter of the inner lead wire 82) is used to funnel the cutend 78 into the spud coil 111, and will also help to wedge the spud coilopen if it is tight.

Light Source Finishing

FIGS. 10A-12C and FIGS. 15A-15B illustrate preferred embodiments of animproved finishing process for manufacturing light sources (e.g.,filament tube 218 in FIGS. 10E and 13A, e.g., arc tube 318 in FIGS. 15Band 13B) for lamps wherein a filament assembly (e.g., 104) or a pair ofarc tube electrodes (e.g., first and second electrodes 306, 308 in FIG.15A) is positioned in a light source body (e.g., body 22) that isflushed and/or exhausted, filled, sealed about foils 76, and otherwisefinished. This light source finishing process is preferably automated tominimize manufacturing cost, and to provide dimensional consistency frompart to part. Furthermore, one or more light source finishing processescan be incorporated as a portion of an assembly line, preferablyautomated, that makes light sources and lamps according to theinvention.

The improved light source finishing process is inventive in thatinventive equipment (e.g., a filament tube light source finishing stand148, as in FIG. 10B, or an arc tube light source finishing stand 148′,as in FIG. 15A) utilizes inventive features of component parts of theinventive light sources described herein. Exemplary embodiments of theinventive light source finishing process will be described hereinbelow,the process comprising at least partial evacuation, flushing, filling,and sealing of a light source (e.g., filament tube or arc tube). Thedescribed process embodiments are exemplary of a variety of finishingprocess methods and schedules, including both pump-flush and/orthrough-flush methods, that can be accommodated by the inventive lightsource finishing equipment. Likewise, the illustrated light sourcefinishing stands 148, 148′ are exemplary embodiments of a variety ofconfigurations of light source finishing equipment that can incorporateelements and features of the inventive equipment and light sourcecomponents.

FIG. 10A shows a finishing head 150 in a cross-sectional view, and FIGS.11A and 11B are a top view and a side cross-sectional view,respectively, that show details of an inner tube assembly 172 that ispart of the finishing head 150. Also shown is an exemplary filamentassembly 104, suitable for use with the finishing head 150, that hasbeen positioned in the finishing head 150 according to the invention.For the sake of clarity, the filament assembly 104 is notcross-sectioned in the side views, and the vitreous material of the body22 is left un-shaded in the cross-sectional views. The finishing head150 is also referred to as a top finishing head 150 due to configurationdifferences that distinguish it from a colletless bottom finishing head151 (see FIG. 10B) and a colleted bottom finishing head 151′ (see FIG.15A).

The finishing head 150 comprises a block 160 of a suitable material(e.g., stainless steel, and/or with anticorrosive plating) that has acylindrical central chamber 162 with a cylindrical axis CA. The chamber162 is open on one end (e.g., the bottom) that is further drilled toaccommodate the inner tube assembly 172 as described hereinbelow. Atleast two inlets 158 (e.g., first inlet 158 a and second inlet 158 b)access the chamber by means of respective first and second needle valves155 a, 155 b, comprising a first needle valve stem 156 a with a firstneedle valve orifice 157 a, and a second needle valve stem 156 b with asecond needle valve orifice 157 b. The first and second inlets 158 a,158 b and their respective first and second needle valves 155 a, 155 bare designed according to the type and flow rate of gas(es) that theywill be handling. Preferably the first and second needle valves 155 a,155 b (collectively referred to as needle valves 155) are automaticallymanipulated and are suitable for shutting off as well as controllingflow rate.

Coaxial to the chamber 162 is an annular recess 163, also open on thesame one end as the chamber 162. A cylindrical spring bellows 164 issealingly attached to the closed end of the annular recess 163,preferably being attached near a radially outermost periphery of theannular recess 163, such that a shroud gas line 152, controlled by avalve 154, can open into the annular recess 163 but radially within thespring bellows 164. The open end of the spring bellows 164 is sealinglyattached to a washer-like flat annular floating plate 166 that is inturn sealingly attached to an outer tube 168. The outer tube 168coaxially surrounds the central chamber 162 and thus shares itscylindrical axis CA. The outward (e.g., bottom) edge 169 of the outertube 168 is a thinned edge 169 for flexibility. The spring bellows 164functions as a compression spring for biasing the outer tube 168downward in a direction roughly parallel to the cylindrical axis CA. Aninner tube assembly 172 is coaxially mounted in the open end of thechamber 162, with an inner tube 170 protruding beyond (below, furtheroutward of) the outer tube 168. The outward (e.g., bottom) edge 171 ofthe inner tube 170 is a thinned edge 171 for flexibility. The thinnededges 169, 171 are thinner than the remainder of the respective tubes168, 170, but not so thin as to become a sharp knife edge because thatis too weak. For example, rather than feathering the edge, it can beturned down to make a uniformly thinner wall tube 168, 170 at thethinned edge 169, 171, and the outermost end can be polished blunt toruggedize the thinned edge 169, 171 due to the blunt end at the sametime that the polishing helps assure good sealing with the bulged end 16of the body 22. It should be noted that various equivalent structurescan achieve the described purposes of the spring bellows 164 and thefloating plate 166, such as, for example, a springy annular disc-likediaphragm, or for example a separate spring plus an extendable bellowsfor sealing.

Both the inner tube 170 and the outer tube 168 are made from relativelythin walled metal tubing (e.g., stainless steel). Referring to FIG. 10D,it can be seen that the use of metallic components (e.g., 168, 170, 190)for sealingly connecting the finishing head 150 to the body 22 allowsfor sealing bodies 22 that have relatively short lengths of materialbetween the finishing head 150 and a necked in body portion 14 that isheated by a high temperature sealing burner 220 to seal around the foil76. Thus the inventive bulged end 16 in combination with the inventivefinishing heads (e.g., 150) minimizes the amount of expensive vitreousmaterial that is consumed in the manufacture of a finished light source.

Referring now to FIGS. 11A and 11B, the inner tube assembly 172 is astacked assembly of coaxial components comprising a collet 174, which isstacked on a spacer ring 186, which is stacked on a funnel ring 188,which is stacked on the inner tube 170. The inner tube 170 is sealinglyattached to the chamber 162 in a way that makes an approximatelygas-tight seal between the innermost (upper) end of the inner tube 170and the chamber 162 (e.g., by press fitting into a slightly taperedhole). Vertical positioning of the inner tube 170 is accomplished bymeans of a reduced diameter spacer stop 202. The collet 174 isvertically positioned by being trapped between the spacer ring 186 and acollet stop 200 at the top. The funnel ring 188 is optional and can beused to assist in loading the outer lead wire 83 b of the filamentassembly 104 into the collet 183. The funnel ring 188 is substantially aconical washer oriented for funneling the outer lead wire 83 b into acenter hole 183 of the collet 174. The spacer ring 186 is also optional,being an annular ring that cooperates with the optional funnel ring 188in order to position the collet 174 suitably spaced above the funnelring 188. Further funneling effect is achieved by a bottom bevel 185that leads into the center hole 183. Even further funneling effect isachieved when, as illustrated, the cut end 78 of the outer lead wire 83b is an angled cut end 78 b having a radially inset point 79 and anacute cut angle θ (see FIG. 8D). Without the optional funnel ring 188and spacer ring 186, the spacer stop 202 can be repositioned such thatthe inner tube 170 stops against it, thereby trapping the collet 174between the inner tube 170 and the collet stop 200. In any case, thecollet stop 200 and the spacer stop 202 should be positioned such thatthe collet 174 is loosely trapped for allowing free and easy radialexpansion/contraction movement of the collet 174 and its componentparts.

The collet 174 is a spring-closed type of self-closing collet comprisedof three substantially equal sectors 180 a, 180 b, 180 c (collectivelyreferred to as collet sectors 180) that are held together by acircumferentially extending circumferential spring 178 (e.g., a snapring or an o-ring), which is captured in a spring groove 179. The collet174 is substantially cylindrical and has a coaxial center hole 183. Gaspassage through the collet 174 is enabled by longitudinal holes 176through the collet sectors 180 and/or by longitudinal slots 182 betweenadjacent collet sectors 180. An optional top bevel 184 is cut at acollet top 204 junction with the center hole 183 to provide a funnel foreasing the pulling of spurs 80 down through the center hole 183.

There are at least two important variants of the inventive collet 174,both of which are within the scope of the present invention. The primaryembodiment is illustrated in FIGS. 11A and 11B and will be describedfirst. A second, alternate embodiment is a dimensional variant andpossible simplification of the illustrated embodiment and therefore isnot separately illustrated or numbered. The primary embodiment of thecollet 174 is intended to utilize the one or more spurs 80 (i.e., theone-sided spur 80 b, or the double-sided spurs 80 a) for verticalpositioning of the filament assembly 104. In the alternate embodiment,vertical positioning must be established by other, external means (e.g.,a robot arm, not illustrated, that inserts the outer lead wire 83 b intothe collet 174 to a predetermined vertical position).

When the collet sectors 180 are held together such that the collet 174is fully closed, the center hole 183 has an inside diameter Dc. For theillustrated primary embodiment, the hole diameter Dc is dimensioned tobe at least equal to, and preferably slightly larger than, the diameterDw of the outer lead wire 83 b, but not as large as the overall width ofthe wire diameter Dw plus one protrusion distance PD for the spur 80.(If double spur straight cut ends 78 a are being used, then the holediameter Dc can be almost as large as the wire diameter Dw plus twoprotrusion distances PD.) It can be seen that the collet 174, sodimensioned, will open radially against the circumferential spring 178as the spurred cut end 78 is pushed up through the collet 174. Once thespur 80 has passed into the chamber 162 above the collet 174, the collet174 will close around the outer lead wire 83 b to loosely hold itapproximately centered along the cylindrical axis CA. When the outerlead wire 83 b is released, it will drop down until the spur 80 hangs onthe collet top 204, thereby providing vertical positioning of thefilament assembly 104. If a top bevel 184 has been provided, thendepending on its dimensions, the top bevel 184 may be the portion of thecollet top 204 upon which the spur 80 hangs. The collet 174 and thechamber 162 are suitably dimensioned such that the collet 174 has roomto radially expand as needed, but not too much room so that the collet174 remains approximately centered along the cylindrical axis CA.

For an alternate embodiment of the collet 174, the hole diameter Dc isdimensioned to be slightly smaller than the diameter Dw of the outerlead wire 83 b. In this case, the collet 174, so dimensioned, will openradially against the circumferential spring 178 as the cut end 78 (withor without spurs 80) is pushed up through the collet 174. Once the cutend 78 has passed into the chamber 162 above the collet 174, the collet174 will close around the outer lead wire 83 b to grip and hold itapproximately centered along the cylindrical axis CA. When the outerlead wire 83 b is released, it will be held by the collet 174 tomaintain a predetermined vertical positioning of the filament assembly104.

With reference to FIGS. 10A, 10B, and 11C, the finishing head is furtherequipped with a left clamshell 190 a and a right clamshell 190 b(collectively referred to as clamshells 190) for positioning and holdingthe light source body 22 by acting on the inventive bulged end 16. Theclamshells 190 are rectangular plates, each having an abutting edge 196where the left and right clamshells 190 a, 190 b abut when theclamshells 190 are closed (as in FIGS. 10B and 11C). FIGS. 10A and 11Cillustrate a first embodiment of the clamshells 190 wherein theclamshells 190 are hingedly connected to a frame 189 by means of hinges191. Preferably the frame 189 is vertically (longitudinally) fixed ormore preferably is spring biased against the finishing head 150, but isfree to slide a predetermined amount in any direction within ahorizontal (lateral) plane. FIG. 10A shows the hinged first embodimentof the clamshells 190 in an open position, swung downward to create anopening large enough to accept the bulged end 16 of a body 22. FIGS.12A-12C show a second embodiment of the clamshells 190 wherein theclamshells 190 are not hinged, but instead slide horizontally,preferably left and right on a frame 189 that is vertically fixed ormore preferably is spring biased against the finishing head 150, but isfree to slide a predetermined amount in any direction within ahorizontal plane. FIG. 12A shows the sliding second embodiment of theclamshells 190 in an open position, slidingly pulled apart such that theabutting edges 196 are spaced apart enough to accept the bulged end 16of a body 22, but the left clamshell 190 a remains aligned in a commonplane with the right clamshell 190 b. It should be understood that thescope of the invention is intended to include all equivalent means foropening and closing the clamshells 190. For example, the horizontalsliding movement could be in an arc driven by a scissor-like mechanism.

Referring now to FIG. 11C, both embodiments of the clamshells 190provide a circular opening, i.e., a center hole 194 for receiving abulged end 16, wherein each clamshell 190 a, 190 b has a semicircularopening cut out of its abutting edge 196. When the clamshells 190 areclosed as shown, with their abutting edges 196 abutted, the center hole194 has a minimum diameter Dn that is slightly less than a bulged endaverage diameter Db (see FIG. 12A), such that closing the clamshellswill trap a bulged end 16, pushing upwards on the bulged end 16 to holdit against the finishing head 150. A sloped sided, preferably spherical,cavity is formed in the closed clamshells 190 such that the sphericalcavity creates an annular spherical cavity wall 192 having a maximumdiameter Dx where it joins a top (inner) surface 198 of the clamshells190, and a minimum diameter Dn where it joins a bottom (outer) surface199 (see FIG. 10A) of the clamshells 190, thereby creating the centerhole 194. The remaining portions of the abutting edges 196 arepreferably trimmed back a bit so that the clamshells 190 can be closedaround undersized bulged ends 16. As shown in FIG. 12A, the bulged end16 of the light source body has an average diameter Db. The clamshells190 are dimensioned such that the maximum diameter Dx is slightlygreater than the bulged end average diameter Db, and the minimumdiameter Dx is slightly less than the bulged end average diameter Db.The curvature of the cavity wall 192 matches the locus of points tracedby the outermost parts of the bulged end 16 as the bulged end 16 istilted while pressed up against the inner tube 170, i.e., tilting a bodycylindrical axis CAB relative to the inner tube cylindrical axis CA asshown in FIG. 12B.

Actual clamshell dimensions are easily fine-tuned to assure properoperation of the clamshells 190 according to the invention as furtherdescribed with reference to FIGS. 12A-12C, which show a sidecross-sectional view of relevant portions of the finishing head 150 andof a light source body 22 as it is being loaded into the finishing head150. The illustrated portions of the finishing head 150 include an outerportion of the inner tube 170 with its thinned edge 171, surrounded bythe outer tube 168 with its thinned edge 169, an outer portion of thespring bellows 164 that is attached to the outer tube 168 by means ofthe floating plate 166, and clamshells 190 with their frame 189.Operation of the clamshells 190 is illustrated for a sliding embodiment,but similarly applies to operation of the hinged embodiment of theclamshells 190. The inner tube 170 has a cylindrical axis CA and theouter tube 168 is approximately coaxial to the inner tube 170.Preferably the clamshells 190 open and close in a way that maintainsequal spacing from the cylindrical axis CA to the spherical cavity wall192 of each of the clamshells 190 a, 190 b.

In FIG. 12A, a light source body 22 having a body cylindrical axis CABis shown as it is being loaded into the finishing head 150. It can beseen that the body 22 is laterally off center, as well as being tiltedsuch that the body cylindrical axis CAB is at a non-zero angle relativeto the cylindrical axis CA of the finishing head 150. FIG. 12B showsthat as the body 22 was raised into the finishing head 150 (by acompliant holder, not shown), the bulged end 16 interacted with theinner tube 170 and was therefore laterally centered. FIG. 12C shows theresult of closing the clamshells 190 in a first configuration whereinthe frame 189 is horizontally (laterally) fixed with the center hole 194coaxially aligned with the cylindrical axis CA of the finishing head150. Thus the body 22 was also aligned (i.e., the body 22 was madecoaxial with the inner tube 170) by the clamshells 190 as they closedsuch that the spherical cavity wall 192 pressed upward on the lowestportion of the tilted bulged end 16. Furthermore, because of the shapeand dimensions of the spherical cavity wall, preferably aided by avertical spring bias on the clamshells 190, the closed clamshells 190exert continuous inward (longitudinal) pressure on the bulged end 16,thereby maintaining firm contact between the inner tube thinned edge 171and the inside of the bulged end 16. Also, the spring pressure of thespring bellows 164 maintains firm contact between the outer tube thinnededge 169 and the inside of the bulged end 16. In a second configuration,wherein the frame floats in the horizontal plane, it can be seen thatclosing the clamshells 190 will leave the body 22 tilted as shown inFIG. 12B, but will press upward to hold the tilted bulged end 16 againstthe thinned edge 171 of the inner tube 170. This second configurationprovides a certain amount of compliance for tolerating minormisalignment between a top finishing head 150 and a bottom finishinghead 151 (see FIG. 10B), without placing any bending stress on the body22, and furthermore allows the combination of top finishing head 150 andbottom finishing head 151 to achieve alignment of a body 22 being heldbetween them.

FIG. 10A illustrates a first step of the light source finishing processwherein the filament assembly 104 is loaded into the top finishing head150 where it is suspended at a predetermined vertical position by thecollet 174 as described hereinabove. If the light source is to be an arctube (e.g., 318) rather than a filament tube (e.g., 218), then a firstelectrode/foliated lead assembly 302 (see FIG. 15A) can be similarlyloaded into the top finishing head 150.

FIG. 10B illustrates a second step of the light source finishing processwherein the filament assembly 104 is threaded into a light source body22, and the light source body 22 is loaded into the top finishing head150 and also into a colletless bottom finishing head 151. Both the topfinishing head 150 and the colletless bottom finishing head 151 areoriented approximately vertically (e.g., the cylindrical axis CA isapproximately vertical), with the top finishing head 150 being above thecolletless bottom finishing head 151. As described hereinabove, thelight source body 22 is laterally centered and axially aligned with thefinishing heads 150, 151 by means of the interaction of bulged ends 16(top 16 a, and bottom 16 b) with clamshells 190 (top left 190 a, topright 190 b, bottom left 190 c, and bottom right 190 d) and with innertubes 170 (top 170 a, and bottom 170 b). The top finishing head 150 andthe colletless bottom finishing head 151 are substantially axiallyaligned with each other, and at least one of the two finishing heads150, 151 is compliant in its vertical positioning in order toaccommodate slight variations in overall body length L. For example: thetop finishing head can be resting on a bracket (not shown). The body 22can be loaded into the colletless bottom finishing head 151 first,wherein the bottom bulged end 16 b is held by closed bottom clamshells190 c, 190 d; then the body 22 can be raised up around the filamentassembly 104 to be loaded into the top finishing head 150, possiblyraising the top finishing head 150 slightly as a top bulged end 16 apresses upward against a top inner tube 170 a of the top finishing head150. In the case of floating clamshell frames 189, this will also finishaligning the body 22 relative to the combined top finishing head 150 andcolletless bottom finishing head 151. The loading operation is completedby closing the top clamshells 190 a, 190 b. The funnel shape of the topbulged end 16 a helps to guide the hanging filament assembly 104 downinto the body 22, further assisted by the tapered or at leastrounded-off leading/trailing ends 88 of the foils 76. While raising thebody 22, the filament assembly can be further encouraged to thread downinto the body 22 by directing a stream of clean, dry, inert gas downinto and/or through the body 22 (e.g., shroud gas emitted between thetop inner tube 170 a and top outer tube 168 a), optionally evacuated byan evacuation line 153 in the colletless bottom finishing head 151.

The colletless bottom finishing head 151 is mostly equivalent to the topfinishing head 150. For example, the colletless bottom finishing head151 has: a clamshell frame 189 with left and right bottom clamshells 190c, 190 d, respectively, that are equivalent to the left and right topclamshells 190 a, 190 b, respectively; a bottom inner tube 170 b that isequivalent to the top inner tube 170 a; a bottom outer tube 168 bconnected by means of a bottom floating plate 166 b to a bottom springbellows 164 b that is connected at an opposite end to a bottom annularrecess 163 b—all of which are equivalent to corresponding top components(i.e., a top outer tube 168 a connected by means of a top floating plate166 a to a top spring bellows 164 a that is connected at an opposite endto a top annular recess 163 a); and a bottom shroud gas line 152 b,controlled by a valve 154 that opens into the bottom annular recess 163b but radially within the bottom spring bellows 164 b—all of which areequivalent to corresponding top components (i.e., a top shroud gas line152 a, controlled by a valve 154 that opens into the top annular recess163 a but radially within the top spring bellows 164 a).

The colletless bottom finishing head 151 differs from the top finishinghead 150 in ways that include the following. The bottom outer lead wire83 a may not require holding when a filament assembly 104 is suspendedfrom the collet 174 in the top finishing head 150, therefore thecolletless bottom finishing head 151 does not have a collet 174, spacerring 186, or funnel ring 188. In place of the inlets 158 a, 158 b withneedle valves 155 a, 155 b, the colletless bottom finishing head 151 hasan evacuation line 153 controlled by a valve 154, that is connected to acolletless bottom finishing head chamber 173. A colletless bottomfinishing head block 161 is suitably modified to accommodate thedifferences as compared to the block 160 of the top finishing head 150.

The top finishing head 150 and colletless bottom finishing head 151 withsuitable gas, electric, and mechanical connections, combine to form aninventive filament tube light source finishing stand 148 forimplementing the inventive light source finishing process, especiallyfor filament tubes (e.g., 218).

FIG. 15A illustrates a colleted bottom finishing head 151′ that can besubstituted for the colletless bottom finishing head 151 for use insituations wherein it is desirable to hold a bottom outer lead wire 83 a(e.g., in arc tube manufacturing wherein a first electrode assembly 302is held by the top finishing head 150 and a second electrode assembly304 is held by the colleted bottom finishing head 151′). The colletedbottom finishing head 151′ primarily differs from the colletless bottomfinishing head 151 by having a complete inner tube assembly 172comprising the inner tube 170, the funnel ring 188 (optional), thespacer ring 186 (optional), and the collet 174. A colleted bottomfinishing head block 161′ and a colleted bottom finishing head chamber173′ are suitably modified to accommodate the differences as compared totheir respective components in the colletless bottom finishing head 151.

The top finishing head 150 and colleted bottom finishing head 151′ withsuitable gas, electric, and mechanical connections, combine to form aninventive arc tube light source finishing stand 148′ for implementingthe inventive light source finishing process for any double ended lightsource wherein the two lead wires (e.g., first and second foliated leads74 a, 74 b) are not assembled together, the primary embodiment of thisbeing arc tubes (e.g., 318). The arc tube light source finishing stand148′ is essentially the same as the filament tube light source finishingstand 148 with the colleted bottom finishing head 151′ being substitutedfor the colletless bottom finishing head 151. It should be apparent thatthe arc tube light source finishing stand 148′ could also be used forfinishing filament tubes (e.g., 218), as long as a way is provided foraccommodating the bottom outer lead wire 83 a of the filament assembly104.

Referring to FIG. 10B, the end result of the second step of theinventive light source finishing process that utilizes the inventivelight source body 22, filament assembly 104, and finishing heads 150 and151 (optionally 151′) is as follows. The light source body 22 issealingly held in a way that creates a closed system of the finishingheads 150, and 151 or 151′ and the inside of the body 22 for at leastpartial evacuation, for flushing, for filling, and for lead wire sealingby means of a variety of methods and schedules. The smoothly curvedinner surfaces of the bulged ends 16 a, 16 b are double sealed: a firstseal to the thinned edge 171 of the inner tubes 170 a, 170 b; and asecond seal to the thinned edge 169 of the outer tubes 168 a, 168 b.Between the first and second seals a shroud gas (an inert gas, e.g.,argon) is supplied by the shroud gas lines 152 a, 152 b at a slightlygreater pressure relative to ambient air pressure, thereby preventingcontaminating ambient air from leaking into the body 22. The filamentassembly 104 (and its filament 102) is axially centered in the body 22:approximately by the collet 174, and more precisely by the straightenedfoils 76 in the necked-in portions 14. The collet 174, preferablyworking with spur(s) 80, has vertically positioned the filament assembly104 such that the foils 76 are in position for proper sealing in thenecked-in portions 14, and the filament 102 is longitudinally(vertically) centered in the bulb 18. It may be noted that even heatingof the body 22 during shrink sealing is required to maintain propercentering and alignment of the body 22 and the filament assembly 104.

FIG. 10B also illustrates a third step of the inventive light sourcefinishing process. In the third step, the light source body is preparedfor filling by removing contaminated gases (e.g., moist ambient air) bymeans of, for example, a preferred flushing method or, alternately apump-flush method. For example, with the needle valves 155 closed, apartial evacuation of the body 22 can be effected by opening the valve154 of the evacuation line 153 and pumping on the evacuation line 153.Flushing is accomplished by opening the first needle valve 155 a toallow a flushing gas to be passed through the first inlet 158 a, intothe chamber 162, through the holes 176 and/or slots 182 of the collet174, through the body 22, and out the evacuation line 153. If a partialvacuum is drawn before flushing, then this process is a pump-flushmethod, whereas a continuous flushing while pumping on the evacuationline 153 is a through-flush method. As is known, heating the body 22while flushing helps to drive out contaminants, and the flushing gasshould be very dry. A variety of pump-flush and/or through-flush methodsand schedules can be accommodated by the inventive light sourcefinishing stands 148, 148′.

FIG. 10B also illustrates a fourth step of the inventive light sourcefinishing process: filling. Once the body 22 is sufficiently flushed,the first needle valve 155 a is closed, optionally a partial vacuum isdrawn by the still-open evacuation line 153, and then the second needlevalve 155 b is opened to allow a fill gas to be passed through thesecond inlet 158 b, into the chamber 162, through the holes 176 and/orslots 182 of the collet 174, and into the body 22, thereby filling thebody 22 with the fill gas. Once a desired proportion of the flushing gashas been replaced by fill gas in the body 22, the body 22 is ready forsealing as illustrated in FIGS. 10C-10F. An advantageous feature of theinventive finishing head 150 is the small internal volume and smalldiameter of the chamber 162 plus inner tube assembly 172 plus necked-inportion 14. Especially when combined with a small volume bulb 18, thesmall internal volume becomes a pipeline that allows “slugs” of nearlyunmixed gases to pass sequentially through, especially since thepipeline is also a small enough diameter to promote viscous flow ratherthan turbulent flow. Given suitable timing of the needle valves 155, itshould be possible to position a slug of fill gas in the bulb 18 at thetime that a first seal is effected in a bottom necked-in portion 14 b(see FIG. 10C), thereby minimizing the amount of expensive fill gas(e.g., Xenon) needed to fill the bulb 18. The exact amount of Xenon gasneeded could be measured out in an external calibrated volume (notshown) that is opened into the chamber 162.

FIG. 10C illustrates a fifth step of the inventive light sourcefinishing process: making a first seal 210 a. The preferred sealingmethod, illustrated herein, is known as “shrink sealing”, although theinventive light source finishing stand 148, 148′ will accommodate othermethods (e.g., pinch sealing). At a time when it is determined that thebody 22 has been sufficiently flushed and is being filled with the fillgas, a sealing burner 220 is applied to a bottom necked-in portion 14 bof the body 22. For shrink sealing, the second needle valve 155 b and/orthe evacuation line valve 154 are adjusted to create a pressure withinthe body 22 that is near or slightly below ambient pressure, therebyassisting the shrink sealing. In FIG. 10C, a top necked-in portion 14 aillustrates the seal area before sealing, and the bottom necked-inportion 14 b is shown at the completion of shrinking to form the firstseal 210 a. The size, shape, intensity, heating time, etc. for thesealing burner 220 and its flames are adjusted according to knownmethods for shrink sealing. Likewise, the sealing burner 220 may beoscillated for suitably applying heat around the perimeter of the bottomnecked-in portion 14 b. Uniform, even heating is needed in order tomaintain axial alignment of the seal 210 a and therefore of the filamentassembly 104 within. Preferably, sufficient heat is applied such thatthe bottom necked-in portion 14 b will shrink around the foil 76 of abottom foliated lead 74 b to form a hermetic seal between the body 22and the foil 76. Further preferably, sufficient heat is applied suchthat the bottom necked-in portion 14 b will shrink around a bottom innerlead 82 b and at least part of a bottom spud coil 111 b to form an innerlead seal 212 for assisting to hold together the bottom spud coil 111 band the bottom inner lead 82 b, and also for preventing stress at thetransition from the bottom inner lead wire 82 b to the foil 76. Furtherpreferably, sufficient heat is applied such that the bottom necked-inportion 14 b will shrink around a portion of the stretched-out leg 113of the filament 104, for quenching arcs that may occur at end of life ofthe filament tube. Further preferably, sufficient heat is applied suchthat the bottom necked-in portion 14 b will shrink around a bottom outerlead wire 83 b to form an outer lead seal 214 for preventing stress atthe transition from the bottom outer lead wire 83 b to the foil 76, andalso for defining a preferred circular cross-section for the innermostportion of a bell mouth 216 that results from shrinking the innermostend of the bottom bulged end 16 b. As will be seen in the description oflight source mounting hereinbelow with reference to FIG. 14, the bellmouth 216 does not have to be round, and furthermore can be quiteshallow in depth, as long as there is room for an elbow 422 of anelectrical support wire 416.

FIG. 10D illustrates a sixth and final step of the inventive lightsource finishing process: making a second seal 210 b (see FIGS. 10E-10Ffor views of the completed seal). After completion of the first seal 210a, a cooling nozzle 222 begins spraying a coolant 224 (e.g., liquidnitrogen) onto at least a lower portion of the bulb 18 of the body 22 inorder to “freeze” a predetermined amount of the fill gas into the bulb18. For example, the chamber 162 can be sized such that thepredetermined amount equals the slug of gas contained in the closedvolume comprising the chamber 162 (with needle valves 155 closed), theinner tube 170 and the sealed-one-end body 22. By closing the secondneedle valve 155 b, freezing the fill gas will cause a below-ambientpressure within the body 22, thereby assisting in the shrink sealprocess. The sealing burner 220 is applied to the top necked-in portion14 a of the body 22. In FIG. 10D, the top necked-in portion 14 aillustrates the seal area before shrink sealing to form the second seal210 b (shown in FIGS. 10E-10F). The second seal 210 b is formed by ashrink sealing process as described hereinabove for the first seal 210a. After forming the second seal 210 b, the coolant 224 and the variousgas and vacuum lines can be turned off (valves closed); the sealingburner 220 can be extinguished and/or removed; and the clamshells 190can be opened and the completed light source (in this case a filamenttube 218) can be removed from the light source finishing stand 148.Optionally a pilot flow of gas can be maintained in the chambers 162,173 and in the outer tubes 168 as a means for releasing the seal to thebulged ends 16 and also as a means for preventing backflow contaminationof the finishing heads 150, 151.

FIGS. 10E and 10F show two views (rotated 90° one from the other) of thefilament tube 218 finished according to the invention. The first seal210 a and the essentially identical second seal 210 b (collectivelyreferred to as seals 210) are shrunk around the foils 76 of the foliatedleads 74 to form hermetic seals between the body 22 and the foils 76.Preferably, the seals 210 are also shrunk around the inner leads 82 andat least part of the spud coils 111 to form inner lead seals 212 forassisting to hold each spud coil 111 together with a corresponding innerlead 82, and also for preventing stress at the transition from innerlead wire 82 to foil 76. Further preferably, sufficient heat is appliedsuch that the inner lead seals 212 are formed around a portion of thestretched-out legs 113 of the filament 104, for quenching arcs that mayoccur at end of life of the filament tube 218 (i.e., quenching an arcbefore it can reach the more massive inner lead wire 82). Furtherpreferably, the seals 210 are also shrunk around the outer lead wires 83to form outer lead seals 214 for preventing stress at the transitionfrom outer lead wire 83 to foil 76, and also for forming bell mouths 216having a preferred circular cross-section for the innermost portion ofeach bell mouth 216 that results from shrinking the innermost end ofeach bulged end 16. As will be seen in the description of light sourcemounting hereinbelow with reference to FIG. 14, the bell mouth 216 doesnot have to be round, and furthermore can be quite shallow in depth, aslong as there is room for an elbow 422 of an electrical support wire416.

The inventive filament tube light source finishing stand 148, and arctube light source finishing stand 148′ have been described hereinabove,along with process steps for finishing a filament tube 218. Withreference to FIGS. 10A-10D and FIGS. 15A-15B, the process steps forfinishing an arc tube 318 will now be described. In general, only a fewchanges are needed to adapt the inventive finishing stand and finishingprocess steps for finishing arc tubes instead of filament tubes.

FIGS. 10A and 15A illustrates a first step of the arc tube light sourcefinishing process wherein a first electrode/foliated lead assembly 302(instead of the filament assembly 104) is loaded into the top finishinghead 150 where it is suspended at a predetermined vertical position bythe collet 174 as described hereinabove. Similarly, a secondelectrode/foliated lead assembly 304 is loaded into the colleted bottomfinishing head 151′. Vertical positioning of the secondelectrode/foliated lead assembly 304 can be accomplished in at least twoways. If the collet 174 in the colleted bottom finishing head 151′ isdimensioned to grip the bottom outer lead wire 83 a, then verticalpositioning is accomplished by the mechanism that places the secondelectrode/foliated lead assembly 304 into the collet 174. If it isdesired to use a spur 80 hanging from the collet 174, then the arc tubelight source finishing stand 148′ can be inverted when verticalpositioning of the second electrode/foliated lead assembly 304 is needed(e.g., during sealing about the foil 76 of the second electrode/foliatedlead assembly 304).

FIG. 15A illustrates a second step of the light source finishing processwherein the first and second electrode/foliated lead assemblies 302, 304are threaded into a light source body 22, and the light source body 22is loaded into the top finishing head 150 and also into the colletedbottom finishing head 151′. As described hereinabove, the light sourcebody 22 is laterally centered and axially aligned with the finishingheads 150, 151′ by means of the interaction of bulged ends 16 withclamshells 190 and with inner tubes 170. The top finishing head 150 andthe colleted bottom finishing head 151′ are axially aligned with eachother, and at least one of the two finishing heads 150, 151′ iscompliant in its vertical positioning in order to accommodate slightvariations in overall body length L. The funnel shape of the bulged ends16 helps to guide the first and second electrode/foliated leadassemblies 302, 304 into the body 22, further assisted by the tapered orat least rounded-off leading/trailing ends 88 of the foils 76. The firstand second electrode/foliated lead assemblies 302, 304 can be furtherencouraged to thread into the body 22 by directing a stream of clean,dry, inert gas into and/or through the body 22 (e.g., shroud gas emittedbetween the inner tube 170 and outer tube 168). Also, threading of thesecond electrode/foliated lead assembly 304 can be assisted by invertingthe arc tube light source finishing stand 148′ while the body 22 isapplied over the second electrode/foliated lead assembly 304.

Referring to FIG. 15A, the end result of the second step of theinventive light source finishing process that utilizes the inventivelight source body 22, first and second electrode/foliated leadassemblies 302, 304, and finishing heads 150 and 151′ is as follows. Thelight source body 22 is sealingly held in a way that creates a closedsystem of the finishing heads 150, 151′ and the inside of the body 22for at least partial evacuation, for flushing, for filling, and for leadwire sealing by means of a variety of methods and schedules. Thesmoothly curved inner surfaces of the bulged ends 16 are double sealed:a first seal to the thinned edge 171 of the inner tubes 170; and asecond seal to the thinned edge 169 of the outer tubes 168. Between thefirst and second seals a shroud gas (an inert gas, e.g., argon) issupplied by the shroud gas lines 152 at a slightly greater pressurerelative to ambient air pressure, thereby preventing contaminatingambient air from leaking into the body 22. The first and secondelectrode/foliated lead assemblies 302, 304 (and their correspondingfirst and second electrodes 306, 308) are axially centered in the body22: approximately by the collets 174, and more precisely by thestraightened foils 76 in the necked-in portions 14. The collet 174,preferably working with spur(s) 80, has vertically positioned thefilament assembly 104 such that the foils 76 are in position for propersealing in the necked-in portions 14, and the first and secondelectrodes 306, 308 are longitudinally (vertically) positioned atpredetermined locations relative to the bulb 18 (determined by shanklengths between electrodes and foils).

FIG. 15A also illustrates a third step of the inventive arc tube lightsource finishing process. In the third step, the light source body isprepared for filling by removing contaminated gases (e.g., moist ambientair) by means of, for example, a preferred flushing method or,alternately a pump-flush method, as described hereinabove.

FIG. 15A also illustrates a fourth step of the inventive arc tube lightsource finishing process: filling. Once the body 22 is sufficientlyflushed, the first needle valve 155 a is closed, optionally a partialvacuum is drawn by the still-open evacuation line 153, and then thesecond needle valve 155 b is opened to allow a fill gas to be passedthrough the second inlet 158 b, into the chamber 162, through the holes176 and/or slots 182 of the collet 174, and into the body 22, therebyfilling the body 22 with the fill gas. Once a desired proportion of theflushing gas has been replaced by fill gas in the body 22, the body 22is ready for a first seal. An advantageous feature of the inventivefinishing head 150 is the small internal volume and small diameter ofthe chamber 162 plus inner tube assembly 172 plus necked-in portion 14.Especially when combined with a small volume bulb 18, the small internalvolume becomes a pipeline that allows “slugs” of nearly unmixed gases topass sequentially through, especially since the pipeline is also a smallenough diameter to promote viscous flow rather than turbulent flow.Given suitable timing of the needle valves 155, it should be possible toposition a slug of fill gas in the bulb 18 at the time that a first sealis effected in a bottom necked-in portion 14 b (see FIG. 10C), therebyminimizing the amount of expensive fill gas (e.g., Xenon) needed to fillthe bulb 18.

FIGS. 10C and 15A illustrate a fifth step of the inventive arc tubelight source finishing process: making a first seal 210 a. Although FIG.10C adequately illustrates the act of sealing the body 22 about the foil76, it should be apparent by comparison with FIG. 15A that anillustration of arc tube sealing can be perfected by replacing thecolletless bottom finishing head 151 with the colleted bottom finishinghead 151′, and by replacing the filament assembly 104 with the first andsecond electrode assemblies 302, 304. One further change is required inthe case of making the first seal 210 a when the collet 174 in thecolleted bottom finishing head 151′ is dimensioned such that the secondelectrode assembly 304 must be hanging from a spur 80 hooked over thecollet 174 in order to attain a desired vertical positioning: in thiscase, the arc tube light source finishing stand 148′ must be inverted180 degrees to place the colleted bottom finishing head 151′ on topduring the making of the first seal 210 a. The preferred sealing method,illustrated herein, is known as “shrink sealing”, although the inventivelight source finishing stand 148, 148′ will accommodate other methods(e.g., pinch sealing). At a time when it is determined that the body 22has been sufficiently flushed and is being filled with the fill gas, asealing burner 220 is applied to a bottom necked-in portion 14 b of thebody 22. For shrink sealing, the second needle valve 155 band/or theevacuation line valve 154 are adjusted to create a pressure within thebody 22 that is near or slightly below ambient pressure, therebyassisting the shrink sealing. In FIG. 10C, a top necked-in portion 14 aillustrates the seal area before sealing, and the bottom necked-inportion 14 b is shown at the completion of shrinking to form the firstseal 210 a. The size, shape, intensity, heating time, etc. for thesealing burner 220 and its flames are adjusted according to knownmethods for shrink sealing. Likewise, the sealing burner 220 may beoscillated for suitably applying heat around the perimeter of the bottomnecked-in portion 14 b. Uniform, even heating is needed in order tomaintain axial alignment of the seal 210 a and therefore of theelectrode/foliated lead assemblies 302, 304 within. Preferably,sufficient heat is applied such that the bottom necked-in portion 14 bwill shrink around the foil 76 of a bottom foliated lead 74 b to form ahermetic seal between the body 22 and the foil 76. Further preferably,sufficient heat is applied such that the bottom necked-in portion 14 bwill shrink around a bottom inner lead 82 b to form an inner lead seal212 for providing a desired bowl shape around and behind the electrode306 or 308, and also for preventing stress at the transition from thebottom inner lead wire 82 b to the foil 76. Further preferably,sufficient heat is applied such that the bottom necked-in portion 14 bwill shrink around a bottom outer lead wire 83 b to form an outer leadseal 214 for preventing stress at the transition from the bottom outerlead wire 83 b to the foil 76, and also for defining a preferredcircular cross-section for the innermost portion of a bell mouth 216that results from shrinking the innermost end of the bottom bulged end16 b. As will be seen in the description of light source mountinghereinbelow with reference to FIG. 14, the bell mouth 216 does not haveto be round, and furthermore can be quite shallow in depth, as long asthere is room for an elbow 422 of an electrical support wire 416.

FIGS. 10D and 15A illustrate a sixth and final step of the inventive arctube light source finishing process: making a second seal 210 b (seeFIG. 15B for a view of the completed seal). Although FIG. 10D adequatelyillustrates the act of sealing the body 22 about the foil 76, it shouldbe apparent by comparison with FIG. 15A that an illustration of arc tubesealing can be perfected by replacing the colletless bottom finishinghead 151 with the colleted bottom finishing head 151′, and by replacingthe filament assembly 104 with the first and second electrode assemblies302, 304. One further change is required in the case of making thesecond seal 210 b when the collet 174 in the colleted bottom finishinghead 151′ is dimensioned such that the second electrode assembly 304must be hanging from a spur 80 hooked over the collet 174 in order toattain a desired vertical positioning: in this case, the arc tube lightsource finishing stand 148′ was inverted for the first seal 210 a, andmust now be inverted 180 degrees again to place the colleted bottomfinishing head 151′ back at the bottom during the making of the secondseal 210 b. After completion of the first seal 210 a, a cooling nozzle222 begins spraying a coolant 224 (e.g., liquid nitrogen) onto at leasta lower portion of the bulb 18 of the body 22 in order to “freeze” apredetermined amount of the fill gas into the bulb 18. By closing thesecond needle valve 155 b, freezing the fill gas will cause abelow-ambient pressure within the body 22, thereby assisting in theshrink seal process. If desired, other solid or liquid phase arc tubelight source ingredients (e.g., mercury and/or metal halide pellets) mayalso be dropped into the arc tube body 18 by known means (e.g., an inlettube or passage, not shown, that opens into the inner tube 170). Thesealing burner 220 is applied to the top necked-in portion 14 a of thebody 22. In FIG. 10D, the top necked-in portion 14 a illustrates theseal area before shrink sealing to form the second seal 210 b (shown inFIG. 15B). The second seal 210 b is formed by a shrink sealing processas described hereinabove for the first seal 210 a. After forming thesecond seal 210 b, the coolant 224 and the various gas and vacuum linescan be turned off (valves closed); the sealing burner 220 can beextinguished and/or removed; and the clamshells 190 can be opened andthe completed light source (in this case an arc tube 318) can be removedfrom the arc tube light source finishing stand 148′. Optionally a pilotflow of gas can be maintained in the chambers 162, 173′ and in the outertubes 168 as a means for releasing the seal to the bulged ends 16 andalso as a means for preventing backflow contamination of the finishingheads 150, 151′.

FIG. 15B shows a single view of the arc tube 318 finished according tothe invention. It should be apparent that another view, rotated 90°,would appear the same except for the first and second seals 210 a, 210 bwhich would be viewed edgewise to the foils 76, as shown for a filamenttube 218 in the view of FIG. 10E. It should be understood that the scopeof the invention includes light sources 218, 318 that have a first seal210 a that is rotated at a random angle relative to the second seal 210b. The first seal 210 a and the essentially identical second seal 210 b(collectively referred to as seals 210) are shrunk around the foils 76of the first and second electrode assemblies 302, 304 to form hermeticseals between the body 22 and the foils 76. Preferably, the seals 210are also shrunk around the inner leads 82 to form inner lead seals 212for providing a desired bowl shape around and behind the electrode 306or 308, and also for preventing stress at the transition from inner leadwire 82 to foil 76. Further preferably, the seals 210 are also shrunkaround the outer lead wires 83 to form outer lead seals 214 forpreventing stress at the transition from outer lead wire 83 to foil 76,and also for forming bell mouths 216 having a preferred circularcross-section for the innermost portion of each bell mouth 216 thatresults from shrinking the innermost end of each bulged end 16. As willbe seen in the description of light source mounting hereinbelow withreference to FIG. 14, the bell mouth 216 does not have to be round, andfurthermore can be quite shallow in depth, as long as there is room foran elbow 422 of an electrical support wire 416.

Lamp Assembly

A feature of the present invention is that the inventive light sources(e.g., filament tubes 218 and arc tubes 318) can be simply andinexpensively mounted in a variety of lamp products, of which twoembodiments are provided as examples hereinbelow. Many moreconfigurations should become evident given the teaching of the presentdescription.

FIG. 13A shows a first of many possible exemplary embodiments of aninventive light source 450 (in this case, two filament tube lightsources 218 a, 218 b) being mounted in a type of lamp that is a generalservice incandescent lamp 400. The incandescent lamp 400 has atransparent or translucent bulb/outer jacket 402 and an electricallyconductive base 404 comprising an eyelet 406 and a screw-threaded shell408. Fixed within the bulb 402 is a nonconductive stem 410 and a post414 for supporting the two filament tube light sources 218 a, 218 b. Afirst filament tube light source 218 a has a first outer lead wire 83 aand an opposed second outer lead wire 83 b, and a second filament tubelight source 218 b has a third outer lead wire 83 c and an opposedfourth outer lead wire 83 d. Electrical connections are provided forconnecting the first and second filament tube light sources 218 a, 218 bin series, thereby forming a “Gemini Lamp”. A first stem leadwire 412 a(optionally including a fuse 407) is electrically and mechanicallyconnected between the eyelet 406 and a first electrical support wire 416a that is nonconductively attached to the stem support post 414 (e.g.,embedded in a glass bead on the post) and electrically and mechanicallyconnected to the first outer lead wire 83 a and to the first filamenttube light source 218 a by means of a first inventive electrical supportconnection 420 a (further detailed hereinbelow with reference to FIG.14). A connecting electrical support wire 418 provides series electricalconnection between the second outer lead wire 83 b (on the firstfilament tube light source 218 a) and the third outer lead wire 83 c (onthe second filament tube light source 218 b) by means of respectivesecond and third electrical support connections 420 b and 420 c.Furthermore, the connecting electrical support wire 418 also helpsprovide support for the first and second filament tube light sources 218a, 218 b by means of being attached to the stem support post 414 (e.g.,embedded in a glass bead, or welded to a metallic stem support post414). A second stem leadwire 412 b is electrically and mechanicallyconnected between the shell 408 and a second electrical support wire 416b that is nonconductively attached to the stem support post 414 andelectrically and mechanically connected to the fourth outer lead wire 83d and to the second filament tube light source 218 b by means of afourth electrical support connection 420 d.

Cost saving embodiments of the present invention that should beconsidered within its scope are envisioned wherein, for example, thestem support post 414 is eliminated and the first and second electricalsupport wires 416 a, 416 b are replaced by the first and second stemlead wires 412 a, 412 b, respectively, which are directly connected,electrically and mechanically, to the first and second filament tubelight sources 218 a, 218 b by means of inventive electrical supportconnections 420. Known means of strengthening the first and second stemleadwires 412 a, 412 b and the connecting electrical support wire 418should be adequate to support the two filament tube light sources 218 a,218 b in a desired configuration under normal handling and operatingconditions.

FIG. 13B shows a second example of an inventive light source 450 (inthis case, an arc tube light source 318) being mounted in a type of lampthat is a sealed beam headlamp 470. The sealed beam headlamp 470 has areflector 472 and lens 473 and a pair of ferrules 474 a, 474 b locatedat the base of the reflector 472. The ferrules 474 a, 474 b arerespectively connected to a pair of electrical terminals 478 a, 478 b.The arc tube light source 318 is both supported and electricallyconnected across the pair of ferrules 474 a, 474 b by first 482 a andsecond 482 b electrical support wires that are electrically andmechanically connected to first and second outer lead wires 83 a and 83b, respectively. A first ferrule 474 a is electrically and mechanicallyconnected (e.g., by brazing) to the first electrical support wire 482 a,which is in turn electrically and mechanically connected to the firstouter lead wire 83 a and to the arc tube light source 318 by means of afirst inventive electrical support connection 420 a. Similarly, a secondferrule 474 b is electrically and mechanically connected to the secondelectrical support wire 482 b, which is in turn electrically andmechanically connected to the second outer lead wire 83 b and to the arctube light source 318 by means of a second inventive electrical supportconnection 420 b. It may be noted that the electrical support wires 416,418, 482 can have any desired cross-section, e.g., round, square,ribbon, etc.

Another feature of the present invention is an electrical supportconnection 420 (e.g., first, second, third, and fourth electricalsupport connections 420 a, 420 b, 420 c, and 420 d, respectively) thatis enhanced by the flared-out bell mouth 216 and/or bulged end 16 oneach end of the inventive light sources 218, 318 (e.g., filament tubelight source 218 shown). FIG. 14 shows a representative bell mouth 216and bulged end 16 formed around an outer lead wire 83 that extends froman end of a light source 218. The bulged end 16 comprises anoutward-opening cavity about the outer lead wire 83, and the cavity isoptionally deepened as desired by the bell mouth 216. The electricalsupport connection 420 comprises an elbow 422 formed in an electricalsupport wire 416, 482 (e.g., 416 shown) such that the elbow 422 loopsinto the bulged end 16 of the bell mouth 216. The elbow 422 thus hooksthe bulged end 16, thereby mechanically securing the light source 218,318 given a holding force Fh that presses the elbow 422 into the bulgedend 16. The holding force Fh may be provided by attaching the elbow 422to the outer lead wire 83 (e.g., by welding), in which case theelectrical support wire 416, 482 can end after the point of attachment(not shown). Preferably, the electrical support wire 416, 482 is formedin a loop 424 (e.g., the electrical support wire 416, 482 extends beyondthe elbow 422 outward of the bulged end 16 and into a reverse-bent leghaving a connection 426 (e.g., a crimped hook) that mechanically andpreferably also electrically connects (provides an attachment of) theelectrical support wire 416, 482 to the outer lead wire 83. Preferablythe holding force Fh is applied to the loop 424 while the connection 426is being made, thereby placing the outer lead wire 83 in tension formaintaining the holding force Fh and thereby assuring a secured lightsource 218, 318. Even without any significant magnitude of holding forceFh, simply hooking the elbow 422 within the bulged end 16 whileconnecting the electrical support wire 416, 482 to the outer lead wire83 will provide a desirable stiffening of support for the light source218, 318 as compared to the prior art. A further advantage of theinventive electrical support connection 420 is that it supports thelight source (e.g., 218) by applying essentially lateral stresses on therelatively strong bulged end 16 but not on the outer lead wire 83, whichonly sees mostly longitudinal tensile stress. This is good because thewire-to-light source seal is relatively strong in tension but is subjectto failure under lateral forces that tend to bend the outer lead wire83. It may be noted that the inventive electrical support connection 420can be employed for mechanically supporting a light source (e.g., 218)while other means are used for electrically connecting the light source(e.g., 218).

Gemini Lamp

The incandescent lamp 400 illustrated in FIG. 13A is a preferredembodiment of a “Gemini Lamp”, wherein the incandescent light source 450within the outer jacket 402 comprises two halogen filament tubes 218 a,218 b that are electrically connected in series, preferably with thefilament tubes 218 mounted in a crossed configuration as shown(preferably crossing at an approximately 90° angle), thereby minimizingthe amount of light from one filament tube (e.g., 218 a) that is blockedby the other (e.g., 218 b). Also preferably the outer jacket 402 is aninexpensive standard bulb of thin common glass (e.g., soda-lime glasswith an average wall thickness of about 0.020″). Further preferably theouter jacket 402 is filled with an inexpensive dry inert gas (e.g.,Nitrogen), or evacuated.

There are many consumer advantages provided by the Gemini Lamp 400, andutilization of various inventive features disclosed herein are intendedto significantly cost-reduce the Gemini Lamp 400 by providing means formass production of inexpensive filament tubes 218 and means for theirmounting in an outer jacket 402, thereby placing double-filament-tubegeneral service lamps within a price range acceptable to householdconsumers. One of many advantages is a lamp efficacy improvement that isprovided by the stretched-out leg 113 on either end of the coiled-coilfilament 102. The stretched-out leg 113 design is more efficient thanconventional coiled-coil filaments having single coil legs that consumesome electrical power without producing any appreciable light. Ingeneral, the Gemini lamp utilizes every scrap of advantage to yield, intoto, a much more overall advantageous design.

Significant safety advantages result from the inventive design. TheGemini lamp is a combination of two halogen lamps (e.g., filament tubes218) in series, each one operating at half of the line voltage, and athalf of the total lamp wattage. At the end of life in a halogen lamp,filament burnout generally produces a break in the cooler running end ofthe filament where failure occurs because of “notching”. An arc canstart, jumping the break in the filament, and then quickly spreading toan arc across the whole length of the filament, thereby heating the fillgas to high temperatures, enough to potentially explode the filamenttube 218. The Gemini Lamp 400 has only half of the line voltage acrosseach filament tube 218, thereby decreasing the likelihood of arcing inthe first place, and if it occurs anyway (e.g., in a first filament tube218 a), the still-burning series-connected second filament tube 218 bwill act like an arc tube ballast and will limit the arc current to aharmless level such that the arc cannot heat the fill gas enough toexplode the failed first filament tube 218 a. Further protection isprovided by the stretched-out leg 113 of the filament 102 (see FIGS. 9Band 10F) that is positioned at the cooler ends of the filament 102 wherethe break generally occurs. Since the stretched-out leg 113 has verylittle mass, it burns back during arcing at a very high speed, and islost to the arc when it burns into the inner lead seal 212.Decomposition products of vaporized quartz provide a cooling effect thattends to snuff out the arc as the wire of the filament leg 113 meltsback into the quartz of the inner lead seal 212. This quenching of thearc appears to occur even faster than a fuse wire can melt in responseto the arc. (Fuse wires are typically incorporated into one or both ofthe leadwires 412 where they pass through the base 404.) Even furtherprotection is provided by using a filament tube body 22 having a verysmall diameter D1 of a circular cross-section, especially in the shrinksealed inner lead seal 212, all of which combine to provide anextraordinarily high burst strength. Side by side testing was conductedto compare failure mode of 100 W, 120V Gemini Lamps 400 (with two seriesconnected 50 W, 60V halogen filament tubes 218 a, 218 b) versus lampshaving the same outer jacket 402 but containing only one standardhalogen filament tube (e.g., 1100) of the same total lamp operatingvoltage (120V) and wattage (100 W). Failure was provoked by ramping upthe lamp's line voltage until the tested lamp arced out. Theconventional lamps 1170 all failed violently, wherein the arc explodedthe quartz body (e.g., 1010). In contrast, the Gemini Lamps 400 allfailed passively, wherein one of the two filament tubes 218 arced out,but did not explode.

The inventive lamp 400 provides significant cost savings when comparedto prior art lamps (e.g., 1170 in FIG. 1B). Gemini Lamp 400 componentsare fewer and cost less than components of comparable same-wattagequartz-halogen lamps. For example, the light source bulb 22 requiresvery little expensive quartz material, while the two filaments 104combine to use almost the same length of tungsten wire of the samediameter, if not less length (due to the use of a more energy-efficientstretched-out leg 113 on a coiled coil filament 102). For example, theone piece foliated lead 74 efficiently uses a shorter length of smallerdiameter molybdenum wire 42 and doesn't need foil that is inefficientlywelded together in common three-part foliated leads. For example, thesmall volume light source body 22 uses less of an expensive fill gas(e.g., Xenon), lesser still when the inventive finishing stand 148 andlight source finishing process are employed. For example, the foliatedleads 74 and the light source bodies 22 are efficiently mass-producedwith virtually no waste. For example, expensive quartz cutoff saws arenot needed to produce the bodies 22. For example, because of the safefailure mode of the Gemini Lamp 400, an inexpensive common outer jacket402 can be used instead of “coke-bottle” enclosures with wallthicknesses approaching 0.250″. For example, the stiffness of thestretched-out legs 113 and the shorter filament 104 (due to half thevoltage and half the wattage) effectively shortens the unsupported spanof the filament and reduces its sag and twisting, such that a smallerbody diameter D1 can be employed, thereby reducing its cost. The halfwattage filament also allows a smaller diameter body than a full wattagefilament for the further reason that heat loading on the body is cut inhalf for the half wattage filament.

Although the invention has been illustrated and described in detail inthe drawings and foregoing description, the same is to be considered asillustrative and not restrictive in character—it being understood thatonly preferred embodiments have been shown and described, and that allchanges and modifications that come within the spirit of the inventionare desired to be protected. Undoubtedly, many other “variations” on the“themes” set forth hereinabove will occur to one having ordinary skillin the art to which the present invention most nearly pertains, and suchvariations are intended to be within the scope of the invention, asdisclosed herein.

1. A process for manufacturing a light source body, the body comprisinga central tipless bulb having a first outside diameter and the bodybeing bookended by two diametrically opposed transitional portions eachnecking down to a tubular necked-in portion having a second outsidediameter smaller than the first outside diameter; the process comprisingthe steps of: providing a length of tubing having an outside diameter noless than the first outside diameter; forming a stretched-out portion ofthe tubing having the second outside diameter by heating the tubingwhile placing the tubing in tension; moving to keep the heatingconstantly centered in the stretched-out portion; cutting thestretched-out portion to form two necked-in portions: one for a rightend of a first light source body, and one for a left end of a secondlight source body; and advancing the tubing such that the forming,moving, and cutting steps can be repeated to form a right end necked-inportion for the second light source body, thereby completing formationof the second light source body.
 2. The process of claim 1, furthercomprising the step of: heating with a shaped burner for forming thetransitional portions such that each has a shape with a smooth contour,smoothly transitioning between the first outside diameter and the secondoutside diameter.
 3. The process of claim 1, further comprising the stepof: controlling the heating and tension such that each transitionalportion has a wall thickness that smoothly varies from a first wallthickness equal to a tubing wall thickness, to a second wall thicknessequal to a different necked-in wall thickness.
 4. The process of claim1, further comprising the step of: providing a controller formaintaining consistency, precision and repeatability such that the shapeand dimensions of each bulb, each transitional portion, and eachnecked-in portion are substantially duplicated or mirrored by the shapeand dimensions of every other bulb, transitional portion, and necked-inportion, respectively.
 5. The process of claim 1, further comprising thestep of: providing a controller for cyclically repeating the successiveprocess steps of forming, moving, cutting, and advancing in order toform a plurality of light source bodies in succession from a singlelength of tubing.
 6. The process of claim 1, further comprising the stepof: automating to provide new lengths of tubing as needed, and to removecompleted light source bodies.
 7. The process of claim 1, wherein thecutting step comprises the steps of: forming a cusped maria in thestretched-out portion; and cutting the tubing by initiating a crackalong the line of a cusp of the cusped maria.
 8. The process of claim 7,wherein the forming step comprises the steps of: heating a relativelynarrow cylindrical band of the stretched-out portion; halting theheating as soon as the tubing in at least the longitudinal center of thecylindrical band becomes plastic; and applying a longitudinalcompression force to the tubing while the cylindrical band cools belowthe glass transition temperature, thereby forming a cusped maria in thecylindrical band.
 9. The process of claim 7, further comprising the stepof: controlling the forming step such that the resulting cusped mariacomprises two substantially duplicate bulged-out portions that join toform the vertex of a cusp.
 10. Light source bodies made by the processof claim
 9. 11. Light source bodies made by the process of claim
 7. 12.Light source bodies made by the process of claim
 1. 13. A process formanufacturing a light source body, the body comprising a central tiplessbulb having a first outside diameter that is bookended by twodiametrically opposed tubular portions; the process comprising the stepsof: providing a length of tubing having an outside diameter no less thanthe first outside diameter; determining a leg portion of the tubing thatextends between a first bulb and a second bulb; and cutting the legportion by the steps of: forming a cusped maria in the leg portion;providing control such that the resulting cusped maria comprises twosubstantially duplicate bulged-out portions that join to form the vertexof a cusp; and initiating a crack along the line of the cusp.
 14. Theprocess of claim 13, wherein the cutting step comprises the steps of:heating a relatively narrow cylindrical band of the leg portion; haltingthe heating as soon as the tubing in at least the longitudinal center ofthe cylindrical band becomes plastic; and applying a longitudinalcompression force to the tubing while the cylindrical band cools belowthe glass transition temperature, thereby forming the cusped maria inthe cylindrical band.
 15. The process of claim 13, further comprisingthe step of: providing a controller for maintaining consistency,precision and repeatability such that the shape and dimensions of eachbulb, each tubular portion, each cut, and each bulged-out portion aresubstantially duplicated or mirrored by the shape and dimensions ofevery other bulb, tubular portion, and bulged-out portion, respectively.16. The process of claim 13, further comprising the steps of: after thecutting step: removing a completed light source body that includes thefirst bulb; advancing the tubing such that the determining step can berepeated on the other side of the second bulb to form a second legportion; cutting the second leg portion by following the steps of eitherthe cusped maria cut-off method of claim 13, or by following the stepsof any non-maria cut-off method; and removing a second completed lightsource body that includes the second bulb wherein the second lightsource body optionally has symmetrical bulged ends on both tubularportions or has one bulged end and one non-bulged end as determined bythe selection of cut-off method.
 17. The process of claim 16, furthercomprising the step of: providing a controller for cyclically repeatingthe successive process steps of a first determining step, a firstcutting step, a first removing step, the advancing step, a seconddetermining step, a second cutting step, and a second removing step inorder to form a plurality of light source bodies in succession from asingle length of tubing.
 18. Light source bodies made by the process ofclaim
 13. 19. A process for manufacturing a light source body, the bodycomprising a central bulb having a first outside diameter, and a tubularleg extending therefrom; the process comprising the steps of: providinga length of tubing having an outside diameter no less than the firstoutside diameter; determining a leg portion of the tubing that extendsfrom a bulb portion of the tubing; and cutting the leg portion by thesteps of: forming a cusped maria in the leg portion; providing controlsuch that the resulting cusped maria comprises two substantiallyduplicate bulged-out portions that join to form the vertex of a cusp;and initiating a crack along the line of the cusp; thereby forming abulged end at the cutoff end.
 20. A light source body made by theprocess of claim 19.